A survival player with no way of changing its gravity, would get stuck if it fell while being on up gravity, I suggest some kind of way to reset player position / just kill them some way after Y=450, like just death after y=450 or start taking damage like the void since your running out of oxygen, it would be great if this could be a gamerule or config

Added a config option for void damage above mox_world_height + 256

oh if its gonna be based off world height I think an additive amount of 100-200 would be fine I only said 450 because there are gonna increase world height in 1.18, but also forgot you can increase height via datapack