It wouldn't be much of an exaggeration to say that Arcane Dimensions is one of the best things to happen to Quake (imo). It's hard to go back to plain old Quake maps after getting spoiled with the kind of quality on display in this mod. Beyond the maps that come with the mod there's also a bunch of great custom AD content; both independent missions as well as mapjams.
if Id decides to make another Quake game (after DOOM Eternal) that's not multiplayer focused, they need to look into older Quake 1 mods such as this and take inspiration on how they should be working on a new quake game.