The short answer is yes and no. I would open up men’s sports to everyone (particularly team sports) and I would have a protected sports class for women - with a separate category for trans-athletes. Eventually I think both trans women and cis-women would throw up top level players. Their skillset might be different but it’d be equally valid.

As for boxing, I think you need to keep weight classes but again these should be gender neutral. This means that heavier set women would likely compete against lighter males. Over a long competitive time frame I think they’d throw up a champion or two. It would be unlikely that a woman would reach both the weight and fitness level required to be a heavy weight boxer. Though I’ve met a few scary mother bears in my time on the front line of social work.