honestly most distros will be fine. what matters more is your desktop environment. pick something light where Bells and whistles can be turned off. i used fvwm for many years on a lower spec system. now I use kde/plasma on wayland.
I’ve used arch and Debian on low spec systems. both were fine. slightly prefer arch cause it’s more up to date
save 80gb for root, sone swap (if not on an ssd) rest for /home. that way reinstalling or switching has minimal risk of losing my /home
i use arch. I’ve got it set up and it works really well for me. I’d only switch if I had some feature I needed in atomic that I can’t have in arch. (not just a feature atomic has, but a feature I need that atomic has)
what has red had done that makes you say the law is meaningless to them?
can u boot Linux of a USB? some USB drives give 1000mbps read so should be nice and snappy for a root fs