miles 🏍️

If you have a spare/old machine, just install a version of Linux onto it. That way if you mess it up badly, you can also practice fixing it without losing anything important.

Easiest to learn by doing, imo.

What type of server do you want to run?

its ok and probably a good idea to google how to do literally anything and everything. i keep a lot of text files with commands to do things so i dont have to remember them.

You sound comfortable with tech that enough the any distro should be good
Main thing I'd recommend is that you stick with bash as your shell, as it's probably the most reminiscent of powershell

Regardless of whether you use it as a distro, the Arch wiki is a good resource on common tasks and utilities you might need.

Linode has a good "first VPS setup" guide where most steps also apply to setting up a home server (you can skip the "instance manager" and hosts editing).

For CLI familiarity, you might want to try OverTheWire's Bandit, a series of puzzles designed to get you used to poking around Linux systems