https://thelongestyard.link/q3a-demo/ (instant, even works on phones)
https://dos.zone/mp/?lobby=ut (scroll down and click Create on CTF-FACE)
They even have multiplayer support.
I hope someone ports UT2K4 someday so I can play ONS-Torlan.
As for id drama, there was plenty after Quake 3. I remember a .plan update from John where he talked about people leaving and people getting fired...I think one of them was John Steed (rest in peace), one of the player modelers who was very active in the modeling community and well liked. Felt like a disaster at the time. I just think there was a lot of conflicting personalities at the company and it was doomed to fail (no pun intended).