I'm not sure how it happened but the code is now working...

Probably - as wrote in some other questions similar to mine - there was a problem of "spaces" between alle the End Sub and the following Sub btn_something_MouseMove, and all it needed was a complete "reset" of those spaces.

As I told in the question, I had an issue with removing part of the code (excel crashing), but cutting the whole code was the solution to prevent it. Then I proceded copy-pasting every Sub top to bottom, saving every time and checking for errors running the code.

It simply started working again. Don't know how or why. Hope this could help someone else!