Mod: immersive-portals-0.4-mc1.16.3-forge.jar

When you create a world, it takes forever to load it. I know that the original Sodium is too not compatible, but there is a fork from author of "Immersive portals" for make it compatible: https://github.com/qouteall/sodium-fabric/releases/tag/ipc1161_1
Maybe you can somehow implement features from this fork for this compatibility?

Possibly. I'm probably going to wait a bit on this until sodium itself does
something with this.