depending on how complicated it is to swap out the hard disk, i’d swap out the windows drive and put in a new one (preferably an ssd, they make a big difference even in older computers) - this way you’ll keep the option to put it back if you’re really lost, you can back up stuff there
mint is a good place to start, no need for coding.
you do need to get adjusted a bit, the complaints about “how difficult it is to do things on linux” is often because people try doing stuff exactly like they did on windows, and sure, you can do exactly the same thing but you need to set up, sometimes compile tools for it - or you can search in the software manager or search on the web for “xy linux alternative”
for instance file sharing - yeah linux supports samba (the windows file sharing protocol), it works, but imo it kinda sucks (but tbf it sucked on windows too), so i started looking for alternatives and just allowing an ssh connection allows you to directly connect to machines with your username, and also allows sftp file transfers, and it works so much better

specifically one of the kellog brothers, the one who did the marketing part. the other wanted to sell cornflakes so that people don’t masturbate