I've found this on Reddit:
https://www.reddit.com/r/quake/comments/evvbmu/improved_collision_detection_for_quake_1/
"Improved collision detection for Quake 1" (by faisal_who)
"... I was able to hack up quakespasm to allow proper collision detection. Bullets can now fly through gaps in the model (since im testing against actual geometry, not a bounding box).
Even though in this vid im using quakeguy as my target, I can actually play the entire quake1 camping with precise collision detection for hitscan attacks (i.e bullets)."
And here is the video:
https://www.youtube.com/watch?v=amzrXf7aJ7M
Interesting. Very very interesting...