Linux

Bazzite is a great distro if you want to jump in and start playing games and getting the software you need to use your computer. The intent behind bazzite seemed to me that it should be accessible enough for non-technical users but provide access to a large library of programs in just a few clicks. It has a few quirks that make it different than other Linux distros if you pick it apart.

Have you ever used command prompt, batch scripts or PowerShell on Windows? That's what BASH, shell scripting or 'the terminal' is equivalent to on Linux (and mac sorta). It's the virtual scalpel you can use to tinker, fix, control, or totally screw up your system. If you don't have important data to lose, then feel free to just try whatever and learn from mistakes you make along the way. If not, then backups are your friend, and be EXTRA careful doing anything as the root user (that's the admin account with total access over the operating system) or any command like sudo (it might even lecture you about it once)

For self-hosting, if you have a spare machine you can just try experimenting on it to your heart's content. If your search-engine skills are good enough then you should be able to fumble your way through install instructions or tutorials. Another alternative is you could rent a VPS and optional domain for <$90/year, which then you can learn about SSH (secure shell) and fiddle with a computer remotely for fun.

People here can probably give you advice or support, if there's a specific problem you're having and you've couldn't figure it out from the documentation and search.