I have the latest version for 1.16.3 i tried a older version of optifine but that also didnt work. It keeps giving me this issue:

The game crashed whilst unexpected error
Error: org.spongepowered.asm.mixin.transformer.throwables.MixinTransformerError: An unexpected critical error was encountered
Afsluitcode: -1

We'll need the full crash report from the crash-reports folder, the single header line is doesn't provide any insights on its own.