[Heaven's Night]

Yes, but also keep in mind that chest shapes and widths aren't easily determined as male/female only as the variance in both sexes could be drawn as an overlapping bellcurve where averages differ to an extent. Also note how this is different depending on ethnicity too and obviously goes over to any physical characteristics, its always like two overlapping bellcurves where average for men and women overlap but slightly differ.

You are correct that men can rarely get a decent cleavage going on, but its not outside of possiblity either. Some dedicated gym rats almost get that with nothing but huge pecs. But I would safely claim that most men can go without much notice while sporting rather large boobs with no effort what so ever. People have such weird way of discerning sex that one characteristics will get ignored if there isn't enough details going to that direction. This is how so many women too get misgendered by accident if they're just androgynous enough for people to make a mistake.

I think guys can keep on growing boobs and not worry much about it, only when it hits a certain point in body proportions and shapes is when it could be problematic. In a similar manner, this is how it will help trans women to cis pass easier. Body proportions are rarely talked about, but in my experience, it is a huge advantage to be curvy enough. I have never been super masculine, but my height and over all size is above average women, I felt that once I hit a certain point of having obvious hourglass/figure 8 shape and big enough boobs for my frame, that's when people started automatically registering me for a woman at all times.

Magic of perception, its more like an art than science as people do it in a weird way.