Just some crash reports that persisted for some mobs. I had to remove the spawn of the respective mobs to stop the server crashing:

• Caiman;
• Skreecher;
• Seal;
  I dont know exactly why these mobs keep crashing the server, but maybe sharing these crash reports might help solving this.
  *btw, this server has some other mods that appears in the crash reports

crash-2023-07-12_14.09.32-server.txt
crash-2023-07-03_23.04.51-server.txt
crash-2023-07-03_19.56.35-server.txt

I was experiencing the same. The common theme seems to be a fluidCollision call that hangs. Removing spawns for entities OP mentioned seems to have fixed it but I had to manually edit NBT files to move players.

crash-2023-11-16_13.12.56-server.txt