Sway sort of does that. It does not resize live, but uses a transparent overlay to show where the window will be. You can do all of the moving and resizing with the mouse this way.

I do not know the answer, but this got me thinking: would it be easier to set up a single login for both session and decryption if /home was on a separate partition and only /home was encrypted?

I went with a used ThinkPad yoga 370. It still only has a dual core while the following Gen has 4 cores, so it seemed there was a price gap. It has thunderbolt 3 for when I want to switch to a bigger screen (with a cheap USB c dock) and USB c charging. Also I wanted to try a touchscreen on a laptop. I should be able to upgrade the single ram stick in it at some point. Running arch with sway without problems.

Edit: I had a x240 for years before. It was fine but I appreciate the higher resolution of the 370, even if I ended up using fractional scaling as it was just a bit too small.

That is incorrect. Both are pretty barebones from the start and have a big pool of extensions to get the functionality that you need. It might be more involved on the vim/nvim side, but that is more of an accessibility VS personalization thing.

There are even sort of distributions for nvim that bring you all the common functionalities already configured.

I only have limited experience on that topic, but when I had to set up my printer, I found the arch wiki very helpful: https://wiki.archlinux.org/title/CUPS

Packages name might not match, but general info should be good for any distro.