In my previous issue, MC-259286 Hostile Mobs barely spawning, I was barely getting any mobs spawning at all, and the few that were seemed to either be drowneds in oceans or the the rest were concentrated in mineshafts. I decided to remove all world generation changes to see if that would fix the lack of mobs spawning.

It did not. Shown in the images below is the results of doing /effect give @e glowing both with and without the pack.

So the bug is that simple datapacks that only change recipes, loot tables, and run functions MASSIVELY decrease mob spawns?

The datapack is inside the zip file by the way