You can't assign all hypotheses 50% prior probability, "Occam's razor" or otherwise.

If you assign H1 and H2 50% probability, then you shouldn't assign H1 & H2 50% probability. If you assign "The world is a simulation" 50% probability, you shouldn't assign "we live in the matrix" 50% probability. If you assign "There is an objective state of affairs, which my senses don't reflect in the expected way" 50% probability, you shouldn't assign "The world is a simulation" 50% probability.

To get around this, you either need to privilege the matrix/simulation hypothesis aggressively, or give up on your beliefs being consistent under even the simplest applications of modus ponens. Neither seems defensible.