Hostile mobs not naturally spawning in the Nether and Overworld on my server

Hostile mobs will not spawn naturally (mostly) in the Nether. Endermen will spawn, and so will blazes but not unless you're near a blaze spawner. There are no piglins, hoglins, or striders to be seen anywhere.

I've had this problem with several Minecraft Java versions in the past, but I was able to resolve this issue by restarting the server, increasing view distance and/or spawn rate, or as a last resort, starting a new server. I've gone through countless tutorials and suggestions online but nothing has worked for 1.16.2.