Is it a mod compatibility issue?
Yes

If it's a mod compatibility issue, please provide the link(s) to the incompatible mod(s)
https://modrinth.com/mod/mpalladium

Minecraft version
1.21.1

Describe the issue
Launch the game with these mods:

fabric-api-0.114.0
immersive-portals-6.0.6
Palladium-1.21x-1.0.9.5
ToadLib-1.21x-1.1.6

1. Load into a world
2. make a nether portal
3. the portal will load, but will not render or something. using the portal works though

Log:
latest.log

THANK YOU! People with Nividia Graphics cards were having an issue with rendering portals, and I had no idea what the issue was.