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://www.curseforge.com/minecraft/mc-mods/irisshaders
https://www.curseforge.com/minecraft/mc-mods/sodium

Minecraft version

1.20.1

Describe the issue

And it was working before updating all my mods (idk if immersive portal was updated or if it's the other mods)

It says to use Sodium 0.5.3 and iris 1.6.11

but those versions doesn't support distant horizons + they are very outdated

first of all, get rid of Iris.