It has been repeated many times, but the idea that cis het men would go to any bother whatsoever pretending to be trans women in order to sexually assault someone when they do so all the time already and are rarely and barely punished for it is patently absurd, and yet we are constantly forced to address this nonexistent, made-up problem by people who just want trans people to disappear and die.
Opinion from a cis het male.
Cis het rapist will not pretend to be a trans anything, would be absolutely offended by the suggestion. Cis het guy may pretend to be a woman for stalking/ID concealment purposes but IMO not going to be used beyond that.
Male would be likely to pretend to be a trans woman only to creep on women. Vanishingly small percentage to be sure.