Turns out the solvability of a board it is a very complex subject 😓
Also, the algorithms that make sure that it is solvable include creating a library of boards that an algorithm was able to solve. Also, that solving algorithm is NP-complete and I'm not sure if this deserves all that work since it's just a first project 😅
For now I'm just going to leave it as random. It is my first game and just a clone. I want to move on to other projects and learn/do new things.
BTW, I did the first click change.