It has taken me a long time to find a voice for an MC trans narrator. I have had trans SCs but my WIP is the first where the narrator MC isn't cis.
There were several reasons.
1. There are parts of life as trans that I prefer not to dwell on. The fear, otherness, the need to always be looking over your shoulder. And I am not the kind of author who glosses over these things. My stories don't take place in Avalon.
2. I write romances and sexuality is messy for a lot of us. It certainly has been for me.
3a. Not wanting to have to prove I had a right to write trans characters. I am an open trans, but generally don't talk much about it. And of course reasons 1 and 4.
3b. Fear of being challenged about how "genuine" my character is. I have already received a polite question about the fact my MC is a butch transfem.
4. Fear of backlash from the haters. There are places I used to promote my stories that I have dropped now that my MC is trans for this very reason. There is that looking-over-your-shoulder stuff again.
6. And yes it's easy. I don't have to explain things. I don't have to worry am I under or over-explaining things.