So, built a couple of mob farms in tha past, different designs and they all worked fine with great drop rates.
However, now I’ve started a new world with 3 friends (same as other times) and I’ve built the standard mob farm with observers and dispensers.
When I’m at my collection point or just around it, mobs are falling, not that much but it works. When I’m at my afk spot (tried different heigts, for different time periods, above the farm and next to the farm) and I’m going to the collection point, there is nothing. However, when I’m going down, there is like 1 huge spike of mobs falling simultaneously with me.
Actually a very strange problem in my opinion, lit up all caves, around it, ... also got this problem when I’m alone on the server.
So I don’t know what the problem is, since the farm itself actually works, but I can’t afk for good rates or just any rates.
My advice would be to start building these farms very high up in the air, in the ocean biome, so you won't need to light up caves. I go in the middle of the ocean and build up to y-195. I've been doing this technique for quite some time now and it works flawlessly, but if you're lighting up 100% of the caves in your area, other players being in different chunks make the farm slower due to other mobs spawning in the world.