Exactly, it's not that mobs don't appear, but they appear very rarely. For example, in the savanna, I only see rhinos; in the forests, I only see the blue jay; in the caves, I only found murmur. I'm playing on version 1.19.3, and I played on earlier versions, and this never happened to me. In creative mode, I can make them appear with the spawn eggs, but naturally, they don't appear. The mod is boring if the mobs don't show up. HELP!

Same thing happening to me, when I go to a swamp anaconda and catfish don't spawn

i have a similar problem im playing with a lot of mods like 20 im on 1.18.2 and the only mob i can find is straddlers in the nether