EVILM0J0 Yup did the Art of War campaign as one of the 1st things before doing the bot matches! Was nice but some were definitely rough, definitely helped a lot know about the whole unit counters mechanics which was definitely nice to have shown in practice
Heretic is nice! If you get GZDoom you can get that one easily and also Hexen, AE is a very big shoutout to Heretic and it's legit fun
Can understand about not modding Diablo, it's very good as is and I don't blame ya; Diablo 2 has a few mods which end up being a bit rebalancing patches with some extra dungeons/things to do for endgame with multiplayer support and active playerbase, then there's stuff like Median XL which basically is a total conversion even if being same progression for dungeons and acts (every classes play veeeeeery differently and got new skills, crafting/cubing also is remade fully and it's very rough to get into since it's a complete different game, didn't like it as much and couldn't do it XD)