I kinda feel you on this. I'm a detransitioning cis woman though, but since I took testosterone my voice is very deep. I like my voice cause it's strong and very clear sounding, but it does make me insecure in public and I think it's a big reason I can't pass as a woman anymore. Sometimes I too just don't say anything, to strangers like cashiers in stores or whatever, when I just don't wanna deal with it and can get away with just nodding or whatever.
Some say my voice sounds feminine like passable despite being low, but I dunno if they're just being kind or if strangers hear me differently from people who know me. Although I do know that tone and flow are more important factors when it comes to sounding feminine. Unless you have a very deep voice, I guess. Mine is somewhere in the baritone range, or low tenor, when speaking.
I'm not sure what I'll do with my voice, if anything. But I might at some point try to make my tone and flow sound more feminine, but keep the pitch where it's at. I've watched some youtube vids about voice training but ugh I don't really get what to do. Also I've no idea what I'd want to sound like. It gets to me that I keep getting misgendered though, whether it's because of my voice or something else. Cause I don't always pass when I'm silent either.
I've on and off thought about choosing muteness, for a variety of different reasons, but ultimately I don't think it's worth it. I think I'd rather continue to not be passing than disable myself even further (as in I already have disabilities and don't need more of them.) But saying that, I do understand why someone would choose muteness, whether selective or for at all times.
Confidence helps me though. Even though I hate not passing and would rather just not deal with it. When I put on an act of being confident, I'm being treated much better. At least being respectfully misgendered is better than being gawked at for it. So yes, fake confidence works too, it doesn't have to be genuine.