OOOohhh well, I've just figured something's wrong.
So after taking it apart and having the footboard set to a height I liked, I figured there is no screws to the left of the drive shaft.
It has been like that for a while but taking a close look to it, there's quite a bit of play in there...
Problem is that the screws probably disappeared at the same time the threads did, so there's no taking one of the right side screws and putting it there since there is no threads.
I guess I need a new driveshaft, what should I be looking into?