Ok well that's a paywall but I went and read the official guidelines on the website, which is a boring PDF report. My understanding: they talked to other athletes and "stakeholders" and agreed that they will handle it on a case by case / sport by sport basis. Anybody can compete in any gender Olympic sport until clear evidence is presented that shows that they have an unfair advantage. And I do mean anyone, they explain that gender is in the mind, and that a natural man who identifies as a woman can apply for a women's competition
I think that's a good result, better than mine, in the sense that various sports have more of less of a problem, and we don't really have all the data to know what's fair. But I still expect that many sports will disallow it if it becomes problematic. It seems like you'd want to track testosterone, but the q&a explains that it doesn't really work. They also do call out that cisgender men have such a "disproportionate advantage" compared to cisgender women, and so categories are required...
They've managed to tow a really careful balance here, between affirming trans ppl and also being ready to lay down bans in situations that arise