I've built some games in GZDoom (my entry last year, TWAT, was one of them) but I'm moving away from that engine for exactly that reason. What I've found is that with retro engines, there are hard limits on what you can do, at least while maintaining your sanity. GZDoom is about as flexible as it gets, but it still doesn't support (for example) skeletal animation, video playback, or a robust custom GUI (ZScript might have changed the last one). If you need any of those you're straight up out of luck. It could be an interesting challenge but it's not my thing.
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Oh yes, I remember TWAT, I played it and the final boss killed me as I ran out of ammo (it must have been very close to death itself). :D
I also experienced older engines to be a lot more prone to parts of your project just disintegrating (map data, mostly), kind of, or simple things taking forever to do. Though using something like the Build engine (if there's even a "generic" version of that around, I haven't looked) for a jam game might be a fun change some time!