I ship everything all around - het, slash, threesomes (and moresomes) in all configurations. I'm all for both vaginas and dicks. But majority of trans smut I've come across is utterly indistinguishable from het smut asides from both parties using the same pronouns.
I think the biggest culprit here is that most smut tends to be pwp, so genitalias touching makes up 98% of the story. It might be different in a longer fic that gets to explore the character's transness outside of sex as well. But if you come into a fic for the sole purpose of seeing two dudes getting hot'n'heavy only to get served bog standard piv... yeah I'd dismiss the fic too.