Try the stream version first if not.
This version from ET Legacy
https://www.etlegacy.com
It fixes all the issues and runs perfect.
Yes i know its from 2003 but with the latest version before legacy it hitched and never scaled right.
I guess if you have complete control over the games code its easy for a few people to fix stuff and there is so many maps and mods for this game to some are WOW.
When you give those who are care about the game they keep it alive.