Back up whatever data you want physically on your computer before doing anything. While still using your Mac os, take an external drive you are okay to wipe clean, then reformat it to an .ExFat file type (so both computers can read the drive easily)

I haven’t experimented too much with different distros, but I would say Ubuntu has a Macintosh feel to it to me. Linux mint is what I use for my gaming PC, and it works fine, but between Ubuntu’s and Mint’s terminals, I like Ubuntu’s way more. It’s a bit pedantic, but I just prefer it that way