Profile from someone running an AoF5 server with some extra mods. Someone noticed your Mixin was making falling entities tick quite a bit more than they should.
https://spark.lucko.me/5I9FXgIKBr

net.minecraft.entity.LivingEntity.handler$dcl000$interceptFall() 4.58%

Hopefully this information might help make it better.

Discord talk below.
Wesley1808:
The lifts mod is doing rather expensive entity lookups every time an entity moves to check for lifts to prevent fall damage - rather than prevent it the moment it actually takes fall damage.
if I had to guess from the code it seems like it just runs it for every single living entity that moves.
if I'm right, and you can just change the injection point to when they actually take fall damage normally, that would fix the entire issue