I made a wither skeleton farm in 1.16.1 using this tutorial
the video says that you should get 40 skulls per hour but i'm getting around 8. I spawnproofed the entire area using slabs with a 128 radius and the difficulty is hard. My render distance is 32 and the server view distance is 10. I am using spigot. The light for the farm is below 7 and a screenshot of it is attached. Could anyone help me?
Update: I filled in some areas with slabs to spawnproof them that i missed by using spectator mode to find them and that made the farm give 13 skulls per hour, a 5 skull improvement, but that could've just been because I got luckier that hour. Some Help would be appreciated
edit: using f3, my E shows 8/14 - 10/20 so the mob cap is definitely not the cause of the slow spawn rate.
Perhaps this is your issue? Under the old regime (ie, overworld darkrooms, witch farms, enderman farms in the end, etc), the idea was to prevent mobs from spawning in a large area surrounding your farm so that all those spawns happen inside your farm. This resulted in more frequent spawns because there was effectively nowhere else to go.
Under this new system, the presence of a mob within a given radius of a new spawn attempt is now a failure condition. This means that if there's an endermen too close to the platform then another endermen will not spawn there. The same goes for all the nether mobs that don't spawn via an alternative means (ie, spawner cages in a fortress/bastion, brutes in a bastion, spawn eggs spewed out from a dispenser, command blocks, etc). This new mechanic only applies to the Nether, however, so endermen spawning in the end or zombies/skeletons in your overworld darkroom grinder will still spawn densely.
I followed the same tutorial on a multipayer serve and im not even getting 5 skulls per hour. I did some spawn testing and i only seem to have 1-2 wither skeletons in the span of 5 minutes. I saw your update on going a few blocks and tried lowering my render distance as well but its not working. I doubt this is a player mob cap issue since the spawn rates dont really fluctuate even when im the only one online. If you can i would really appreciate it if you could help me out.