Server crashes around 3 minutes after startup and has very bad lag and wont load chunks. Here is crash report - https://pastebin.com/Vx6qQzqW

The line of code this crash log points to is a simple loop over the items in a player's inventory. There's nothing about that that can cause a crash in isolation, which makes me think this is a compatibility issue.

Does this issue still happen with only mowzies mobs and geckolib installed?

If not, could you please remove/add back half the mods at a time to isolate the incompatible mod?