1) Everything is soldered to the logic board
Also true of many Intel Mac models - the old iMac and Mini did have socketed DDR4 RAM, but newer models use LPDDR (low power) RAM which
has to be soldered to the logic board.
I agree that I don't like having the SSD soldered in. The Mac Studio is partly a solution to that - the SSD is on plug in modules and even though Apple won't sell
upgrades they can be replaced like-for-like if they fail. The studio also has most of the external ports and stuff on replaceable daughter boards.
2) Apple treats customers like slaves, you do not own what you paid for - hardware is tied to icloud accounts
Again, while I don't
like it, that was becoming true of Intel Macs once the T1/T2 chip was introduced (I don't think its strictly iCloud accounts - it's the machine ID embedded in the T1/T2/ASi chip).
I mainly use my computer for watching stuff online, web browsing, a bit of 3D modelling and rendering and very occasional video editing.
64GB of RAM is probably a bit of an overkill for that and you'd have to go to a Mac Studio to match it (of course, video editing/3D rendering is a piece of string - 64GB may be justified for heavy use, and some people would add an extra '0' to that! - have a look at the memory pressure in Activity Monitor on your existing system to see if its ever going out of the green - you could create a RAM disk to mop up 32GB RAM).
Also, anything or nothing could be announced at WWDC next week - but buying a new Mac this week is probably inadvisable.
Bear in mind that while you could get a nice big 4k screen to go with a Mini that would be great for TV & movies and perfectly good to use as a computer screen in native 4k mode, it's not going to be in the same league of sharpness as the 27" 5k.