You are missing the fact thay you get language points for solving one kata in many languages. Overall progress is awarded only once, but language progress is awarded separately.
If you do not care about points for other languages, you can unlock solutions in this language by clocking "unlock solutions" in kata trainer.

https://github.com/codewars/codewars.com/wiki/Troubleshooting-your-solution#how-can-i-see-which-input-causes-my-solution-to-fail

I think you should show what are those test data to us (all of them) because it is very hard for us to fix the bug without knowing what those test datas are

You write a unique string in that field in your profile and you're done.

How can I create a clan?

Why can't we see solutions in other languages?

example, I solved Kata X in Rust, a clan member solved it in Javascript, I can't see their solution.

Not sure what's the point of blocking it if there are no extra points to be gained for completing a single kata in multiple languages. Or am I missing something here?