Tesla could solve most of their problems by firing Musk.

They could have done this a LONG time ago… now the damage is done. Nobody would care he is no longer CEO (although that may help Tesla develop better cars), people are not going to want to drive a Swasticar anyway nor give money to a literal Nazi

Short of selling all his stock and completely disappearing from the public eye, Musk completely destroyed Tesla. There are simply better options that do not include helping/associating with a Nazi