If you need to reimage it, it sounds like you're looking for "Headless Rasbian". As others have said, it is based on Debian.
A lot of stuff I want to learn/practice "work" on windows but are native to Linux, like vim/neovim nmap gcc etc. Is this feasible?
Absolutely. And it's fun.
Am I under estimating what's possible with it?
Haha. Yeah. I read somewhere that the Pi3 is the most capable budget PC ever produced, and I have no reason to doubt that claim.
But you can always do more with it later. May as well start with trying what you're interested in now.