Game crashes on startup

[TheAnonym3000]

Context

Game crashes when i try do start the game (Without giving a crash report, latest.log is provided instead) and throws this Exception: org.spongepowered.asm.mixin.throwables.ClassMetadataNotFoundException: com.simibubi.create.foundation.utility.Couple

Crash Report

https://mclo.gs/atsshdV

[VoidLeech]

You have outdated (versions of) addons (or potentially other mods):
Do note that not all addons have updated to support 6.0 yet;

Make sure all your mods are updated to the latest version, and for addons check whether their changelog mentions that they now support 6.0; the internal changes are big enough that essentially any non-datapack addon will be broken if they haven’t.
I haven't checked mod compatibility beyond the mods I mentioned, you should do some level of investigation in that regard yourself.