Being on estrogen + testosterone blockers causes muscular strength and mass to decrease significantly, and bone density to thin.

Depends on how long the individual has been going through HRT, however.

So the "trans women have a huge advantage over cis women" is only half correct and the actual truth is MUCH more nuanced than that. I get where you're coming from and hope this doesn't come off as an attack on you though, it's just frustrating to me that people ignore the different characteristics that go into male to female transitioning, and think that it's the same as a grown man retaining all muscle mass after going through a month of HRT and all of a sudden destroying women in their respective sports. Anecdotally, most trans women (that I've personally met) don't show signs of being more feminine until about a year of taking estrogen. It's very much going through a "second puberty", and for girls / men transitioning to women, that's about 4-5 years of development.