This crash happens during world-gen for both single player and server, but only servers give logs

https://paste.ee/p/Yct9B

From the above crash it mentions another mod, so I removed that mod to see if the issue is fixed, but it only leads to another mod being mentioned.

https://paste.ee/p/QsrDb

That made me think it's the problem with this mod, the version is the latest version for 1.16.5.

The logs appear to have expired, though the most recent version since this post may have fixed this issue. If it still happens with the latest version, please post a new issue here.