Boringly straight man here: I usually dream as myself, but occasionally I’m dreaming that I’m someone else. Could be either a man or a woman. Sometimes I have no body at all.
So I know nothing about how common my style of dreams are, but I don’t see any reason why trans people would have to dream a single persona all the time.
When smart watches were begining to be a thing, a friend of mine bought a smartwatch for like 5$ in Ali express. When I asked him how the watch is he said “I am surprised that even for this low price, they still managed to disappoint me”