So yes, your vintage lenses are definitely an issue with the Z series, which is why I think you personally probably should stick to the D cameras.
I have an 85mm D lens that does not AF on my Z series and it's the only one I had that wasn't compatible (in terms of focusing). All my other F mount lenses I feel are a lot faster on my Z cameras. The AF system as a whole is much more robust on the Z series and the D800 I found was rather slow overall (I shot with a D800 as my main camera for about seven years). I have way more keepers in terms of in-focus images for my kids' sports (lacrosse and swim) on my Z series (even the first gen Z6) than I ever did with my D800, and that's just with single point and manually tracking them. I rarely ever use the built in tracking methods. Mostly I've never tried to learn those and stick to the old-fashioned method. ?
You know a lot more about Nikon vintage lenses and how a camera actually works than I do, so your comment about the manual focus lens metering sort of is over my head. I will say that the 85D does meter through the FTZ, just not focus (I just mounted it to check). But I think you are going back another generation or two of lenses that will neither focus nor meter.
Just getting back into some of the other comments, and this may be more than you cared to know but here's the story on metering, and since I like to ramble maybe what some would call a "beginning of time" answer.
The Nikon F was introduced in 1959, and with it a series of lenses called Auto-NIKKOR lenses. The F was a revolutionary camera. It had a a simple to use bayonet mount, full aperture viewing, could integrate what's called a fully coupled meter(more on that in a second), a metal foil shutter with a 1/1000 max speed, and an instant return mirror(drops back down after the shutter closes unlike, say, a Hasselblad where the mirror stays up until the film is advanced/camera cocked). It was also highly modular, and could be fitted with different focusing screens, viewfinders, film backs, and even a motor drive to configure it for different situations. None of these features was new, and they could all be found on previous cameras, but the F was the first with this combination of features and backed it up with a comprehensive selection of lenses.
The F did not have a built in meter, but was designed to be compatible with one. The earliest clipped on to the front of the camera with a selenium cell, while the next was integrated into the prism housing, then evolved to read off the focusing screen(TTL metering), then modified it so that the center of the screen influenced exposure more so than the outer edges(what we now call center weighted averaging metering).
These meters were all "coupled." What that meant is that the meter was told the ASA of the film(by manually setting it on the meter), the shutter speed by physically resting on top of the shutter speed dial, and the aperture by reading off the lens(more on this in a second). These fed into a simple circuit with a power source, photo cell, and galvanometer. Basically, when the settings would result in underexposure, the needle would be at the "rest" position, if overexposure the needle would peg at its maximum value, and if "just right" it would center over the range of movement against a big pointer.
The way the lens communicated its set aperture to the meter was something of a hallmark of Nikon in the early years. Basically, the lenses have a set of "bunny ears"(I think properly called a meter coupling shoe or often called a metering fork) that are mounted on the aperture ring at exactly f/5.6. A pin on the meter fits into this, and the meter knows where the aperture ring is on the lens.
As a bit of a side note too, when adjusting exposure, to center the metering needle you would turn the aperture ring toward the direction you needed the needle to move. ALL aperture rings on Nikon lenses move the same direction. Nikon meters in manual mode still default to + on the right and - on the left. It's been that way since the first Nikon F meters, and was logical in that context.
In any case, the whole fork and pin thing worked but had its downsides. Since the fork is always at f/5.6, the meter knows the aperture set on the lens. Still, though, in order for a TTL meter to calculate exposure properly, it needs to know how far the lens is set down from its maximum aperture. The only way to achieve that with the Nikon-type system is to tell the meter what the maximum aperture is. On the first generation TTL meters, you had to set this on a dial on the meter.
Nikon got clever and figured out a less tedious way of doing this. Basically, they developed a mechanical system whereby if, after mounting, you twisted the aperture ring to its maximum aperture, the meter would "learn" it. When a new lens was mounted, the mechanism was reset and this was done again. This gets the term sometimes of "Semi-auto indexing." It first showed up on the Nikkormat FTN, but carried over to the Nikon F FTN finder along with the F2 Photomic, Photomic S, and Photomic SB finders. This also gave rise to a familiar sight for Nikon users at the time. Basically, after mounting, on an F or F2 body, you'd generally twist the aperture ring to the minimum aperture to both reset the indexing mechanism and also "grab" the metering pin. You'd then twist it back to minimum(along with a distinctive clicking/ratcheting sound from the camera), after which it would be ready to go. It becomes second nature, but isn't necessarily intuitive and there again was mostly known as a "Nikon thing" to have to do this. Also, as a bit of a sidenote, the Nikkormat bodies(which were the second tier bodies) are even more of a pain since you have to manually reset the metering pin and then set the lens to f/5.6 before mounting to align the pen right. The F and F2 meters work with the lens mounted set to any aperture, although they tend to twist to f/5.6 when dismounting.
Other makers, Canon in particular, had figured out how to get full aperture coupled metering without this, so Nikon finally had to grudgingly in the late 1970s give in. Backward compatibility remains a core of Nikons(well with some exceptions) so they designed a system that would work with the existing lens mount. Essentially, what was done first of all was to construct lenses with a "step" on the aperture ring facing the lens mount. Then, a tab that moved concentric with the lens mount was added. The tab would rest against the "step". The step location varied such that when the lens was set to maximum aperture, the tab would be at its rest position. The meter, then, could know if the lens was set to wide open, or how many stops down from wide open it was set. This system was called the "AI" or "Automatic Indexing System." If you look at the alphabet soup on a Nikon lens with an aperture ring, you should still see the letters AI on it even if it incorporates a bunch of other technology. The tab remains on high end DSLRs. It is there on your D700.
Of note also, with the switch to auto-indexing came a bit of a legacy problem. The previous non-AI lenses had their aperture rings fully extended down to the lens mount where they can hit and even break the AI tab. Nikon recognized in the early days that a lot of folks would still have non-AI lenses, and made provisions for them. One of them is that the first AI cameras allow the tab to be moved out of the way. On the F2A/F2AS the tab is pushed up into the metering head. The EL2, FE, FM, F3, and F4 all have a tab that can be "folded over" to get out of the way. This could be fitted by the factory to the F5 and F6 also(I am sorry I didn't get mine done, but maybe should get on it and see if they still do). The Df remains the only DSLR to have this. Also, most manual focus Nikkors have a metering shoe on them, so they will continue to meter just fine with non-AI cameras.
Incidentally, also, the AI system and aperture ring caused issues with weather sealing since it left a gap at the lens mount. Since G lenses eliminate the aperture ring, they can have a complete O-ring seal around the mount.
With AF and computerized cameras came a new way of thinking of things. Cameras that offer a "P" mode or "S" mode have to be able to set the aperture using the stop-down lever on the lens(the one inside the mount). Along with the introduction of the FA, Nikon's first multi-mode shutter priority and program camera, came "AI-s" lenses, which linearized the motion of the aperture lever for this. This AI-s principle is still used on modern non-E lenses to set the aperture. The AF era also brought something else-CPUs in lenses, and aperture control(even in M and A modes) from the camera body. At first this was only relegated to lower tier bodies, or at least the M and A modes being controlled from them, but the F5 was the turning point and introduced the two dial control layout we know today. The CPU, among other things, communicates information about the lens to the camera like its maximum aperture and focal length(both used for metering).
Unless you're a weirdo like me who changes it, if you have modern lenses with an aperture ring and only use modern bodies, you've likely never moved the ring off its minimum setting. They have a lock to allow for this, and typically if you bump it off the minimum setting it gives you an error.
Because of that, a lot of lower end bodies just said "forget the aperture feeler-we just need to make sure the lens is set to minimum aperture" and just have a simple switch to tell that. This is what the FTZ adapter has(although I'd not call it low end). BTW, again since I'm a weirdo, on bodies that are capable of it I use the aperture ring to set the aperture(which actually gives more consistent exposure, but that's another topic of discussion). The Z cameras can't meter with manual focus lenses for this reason(unless they do stop-down metering-I don't know that).
With all of that said, though, because I have a bunch of MF lenses I really like and use, I want a body that can meter them directly as they were meant to be used.
