One of my favorite YouTubers is Zhea from TransVoiceLessons. On her livestreams, then almost half of the questions she gets are along the lines of, "Will voice feminization still work if [insert something here]?" And 99.5% of the time, the answer is, "Yes, it still works with that." I think she's addressed stuttering, too. She does give tons of examples on various things, like on how to cough in a feminine voice, how to yell/whisper in a feminine voice, and do pretty much everything else that's often considered difficult/impossible with a feminine voice. She doesn't stutter, so she can't really give an example of that, but I think it's a lot the same concept as the rest of the stuff she addresses. The 0.5% where she says, "it depends" is usually only to people whose vocal tract is damaged or injured in some way. So, my point is that if you want some confidence this is possible, watch some of her videos, even though it's mostly not stuttering-specific. Here's one of her livestreams: https://www.youtube.com/live/DBzhRDJ5NcQ Also, one of the things that she teaches, that I think is really cool, is how to make your feminized voice your real voice, and not a "fake voice."