A good news is that the people at OldUnreal's took over maintenance of the Unreal Tournament code base after reaching an agreement with Epic Games in 2019. So the old Loki binaries have modern replacement

On Debian based system, you can even generate proper packages using game-data-packager if you have the old CDs or the GOG installer at hand:

game-data-packager ut99 --binary-executables <GAMEPATH>