Custom Mob Not Spawning In Nether-Like Dimension

I don't know the exact solution to the problem, but I know that there are some spawning issues with the nether. Custom biomes, that sort of thing.

If you can't get the mobs to spawn and nobody else knows the solution, then you can try creating a custom mob spawner using procedures. Creating something like a block that checks in an area where ground is can guaranteed spawn mobs using the [World management] Spawn at x, y, z, entity [entityname]. Choose how often it spawns, etc.

It's because only "monster spawning type" mobs spawn in nether, it's really hard to find "creature spawning type" mobs

omg thank you