My game crashes when I try to press the options button, the only mods I am using are Puzzle and Fabric API (latest version)

The crash report says:

The game crashed whilst mouseclicked event handler
Error: java.lang.NoClassDefFoundError: net/coderbot/iris/gui/ShaderPackScreen
Exit Code: 255

Hopefully it's fixed now with the latest version, could you try it?

I can say for sure that the 1.17 version isn't affected by this anymore.
1.16 is no longer supported now.

It looks like the code referring to iris is run even without iris installed, normally it should just not call that class without iris installed...
It should just stop right here.
The mod will soon move to 1.17 and be a core of a big project, I'll make sure everything works by then.