My feet got a bit bigger on T. I had size 6 in women's shoes pre-T. I guess that would be around 4 or 5 in men's sizes if that even exists, as it doesn't seem to be listed. I'm European so looking at some size conversation chart, in EU sizes I mean 36-37. After about a year or two on T my feet required size 39-40 which seems to be roughly 6 or 7 in men's US sizes. But in my country men's shoes in my size don't exist, although I'm fine with buying/wearing women's shoes so it doesn't bother me much.
I always suspected I had higher levels of estrogen before I started taking testosterone, for a number of reasons. I'm 5'6" and while I was still living as a girl before coming out as trans, people kept telling me I had really small feet for my height. I could almost still fit into children's (girl's) shoes in my late teens, they were just one size too small so a bit tight on my toes but wearable for shorter times. I wore them cause they were pink and glittery and I liked that kind of stuff back then, also it was fun.