As you can see from the title above, this is the last message there before Minecraft stops loading.
So yes Minecraft loads for me, then shortly before the end of loading it stops and it is caught in an endless loading loop.
I looked at the log and at the end there was only the message "Reflector Vanilla" and nothing more came after that.

I used the following mods:
"XaerosWorldMap_1.37.2_Fabric_1.20" "Xaeros_Minimap_23.9.3_Fabric_1.20", "Optifine 1.20.1 I5 (and i try I6 too, same result)", "optifabric-1.14.3", "fabric-api-0.85. 0+1.20.1", and "AutoSwitch-Mod-Fabric-1.20.1" that's all. Maybe someone has an idea or a tip would be appreciated.

P.S And a side note, I've already tried it with the 0.92 API, but I immediately get a Code 1 error message, so 0.85.0 still works best.

I got the problem fixed somehow, I don't know how or with what, but it worked.. so this can be closed.