Look out for freebies on Epic Games Store, sometimes they are giving away great old titles, and there will be a bunch of good games before Christmas for sure, as every other year. They even gave away GTA V few years back (but that wasn’t for Christmas)

If you are going to play games from Steam only, there is no need for modding/tinkering. It’s getting a bit more difficult if you want to play games from outside of the Steam Store, like from other game stores, or emulators etc. byt that’s not really hard to do, it doesn’t require coding for sure, all you have to do is to follow guides, and there are many of them on the internet