And I am very "optimistic" I am getting the full specd MBP 16GB Ram and 512GB SSD BUT there were some considerations I was not writing first:
My daily work I am still doing on a 5,5 years old Desktop WIndows PC (intel i5 4460, 8GB Ram,) , which runs at the moment "ok" (atm I am not doing any video editing on my desktop). However, even though people here say having both OS at the same time (Windows/mac) is not a problem or even complementing themselves, I am not sure about it (alone the fact how to get videos from iPhone on the PC is such a pain..).
Therefore I am thinking in the next 1-2 years to need also another Home station, and the new Mac mini just seems optimal for that, since I have a good monitor and don't need an iMac.
Therefore I was thinking 8GB Ram on my laptop will be enough since the main work will still be on my desktop in future.
It sounds like you're making a good call there for a long-term purchase. I tend to upgrade my home computers every 3-5 years, but at work we've got 10-year-old (high-end for the time) iMacs and 9.5-year-old midrange Windows boxes that are still at least usable, so I'm not exactly unfamiliar with getting the most mileage out of computers you can. At least to date, though, "have enough RAM" has been something that helped a lot with that strategy (if you had 4GB in your Windows desktop rather than 8GB, I'd wager you wouldn't be feeling the same way about it).
Basically, my strategy, which hasn't failed me yet, has been: If you're going to be using it for a long time, you should probably overspec a bit to start with. You'll probably thank yourself a few years down the line, and/or be able to squeeze another year or two out of it.
Having a Mini or other desktop to supplement the laptop doesn't really change the equation much. You can certainly compensate for a less-well-equipped laptop by having a second computer to do the heavy lifting, but if you plan on using the laptop for that long you're still not going to want it to be unpleasant to use toward the end of its life.
Also the latest price policy of Apple is very interesting, considering that Apple silicon will decrease prices of all of their future devices and making them cheaper than the Windows competitors... this means people will upgrade more often imo. It's not so painful anymore than it used to be... buying a good specd MBP 16" in the past you didn't want to buy that every 3-4 years (unless money didn't matter for you at all)
We have absolutely no idea what Apple silicon costs Apple to design and fabricate, particularly at the lower volumes of desktop processors relative to mobile ones, so as far as I know any speculation about it costing less than Intel parts is just that. They might be much cheaper for Apple to design and fab, or they might actually cost more. We simply don't have any way of knowing.
An interesting and competing issue is that on one hand, Intel CPUs have stagnated pretty significantly for the past several years, so even an fairly old machine wasn't generally that much slower than a new one, while at least thus far Apple mobile chips have been increasing in performance at a much higher rate, which is why they've recently surpassed Intel parts despite starting out much slower. If Apple is still on the steeper part of the curve, that would point to near-future Macs having the sort of significant speed bumps from one generation to the next that we haven't seen in a while.
On the other, you can as of today buy a MacBook Air that can in many cases compete directly with a top-of-the-line 16" laptop from two weeks ago. This would point to you being able to get
more life out of your old Mac 5+ years from now than is the case today, rather than a faster turnover.
Personally, I don't see any particular reason to assume that the general price points of Apple's small number of models will change significantly. They can obviously sell plenty of computers at those price points, so if they're doing a cost-benefit analysis they're probably going to come at it from the other direction--"We paid Intel $350 for the CPU in this model, so what can we build for $350 to replace it?" The fact that pricing is relatively flat with the M1 transition kind of indicates this is the case, since Apple doesn't like to mess with its margins, and they've demonstrated they can offer a huge boost in performance at the same price point.