is there a version of compose build that everything is open? I try to implement something but everything is marked as internal

No, because the decisions a library makes about what to leave open are intentional - even if you could do this, your implementations could break at any time if implementation requirements are changed even without a major version bump. What are you trying to implement? Maybe there's another way to do it, or you could file a feature request if there isn't.

I am implementing compose in a custom gl context, so it can be used in games

Compose UI? You can use compose core without having to override internal stuff

https://github.com/smallshen/JetpackComposeMinecraft this one is using older version of compose, which most thing is open