I've been running Debian for years. It took me a long while to learn the lessons documented clearly on https://wiki.debian.org/DontBreakDebian , especially the one about frankendebian. These days, I mostly run Stable, and it's been super reliable.

It's not the route I've gone, but lots of people seem to be having success with retired small form factor business machines. Getting a good deal on used business stuff seems to be the key, ideally locally, where they just want to get rid of it compared to ebay. A low-end Intel from 4 years ago is annoyingly good computation per watt.

Also, take your power bill and calculate the cost of a watt for a year. Remember that number for all future purchases. Where I live, it's around $1.50/watt-year. A 60-watt always-on computer gets pricy quickly.

I like DarkViperAU. He's a GTA5 speedrunner, something I had never followed, but his explanations and general style is great for me. His "one hit KO" series, where he attempts to complete GTA5 without taking any damage, is a fun place to start. https://youtube.com/playlist?list=PLAnJ4ZuTYaeGOdVzYfhfZUgjVcyCeYVwO