Sean Nolan

This same issue is plaguing me. At my old (years old) portal to the Nether, I regularly have one or two ghasts spawn EVERY MINUTE; wither skeletons spawn in fortresses as fast as I can kill them, and I can literally watch an area fill to bursting with Piglins over a ten minute period, as they spawn somewhere between three and five a minute.

Yes, they certainly are. My first portal in the Nether from over a year ago is certainly NOT in a soulsand valley biome, yet there are literally over a dozen spawns every ten minutes of ghasts. I've had to rebuild the ground around it with stone because they've destroyed all the netherrack around the portal.

Same problem.  I literally cannot kill them as fast as they respawn in the nether.