Extremely tangential but I think relevant: some of the DOOM mods that are still being made are utterly phenomenal.

It's easy for people to think "Why would you constrain yourself to a DOOM engine when you could use Unity/Godot/Unreal/whatever and have better graphics and more freedom?!", but that's kind of missing the point. The point is figuring out how far you can stretch something, and how to get the most out of something limited.

Blade of Agony, for example, exclusively runs on GZDoom, which while more advanced than the vanilla DOOM engine, is still a lot more limited than Unreal or something, but I think that what they did to really stretch that engine to its fullest extent has made something that's extremely fun, charming, and gives it a distinct look and feel that you simply wouldn't have if you used a "modern" engine.