Exactly. Before you even start to determine how it could possibly made fair (spoiler: it can’t) it needs to be explained how these males - trans or DSDs - are even eligible to be in the female category in the first place. Demonstrate how they are women/females first.
I don't think it's quite that straightforward. You do need to consider why the category delimiter is "female" in the first place, and whether that is the correct dividing line.
Fortunately the easy answer to that is it IS correct, because there ARE two human phenotypes, male and female, each with their own clear performance distributions.
Picking up on something from Emma Hilton yesterday, the highest-athletically-performing humans are basically able-bodied 25-year-old males.
To give other humans a chance you need to have categories. The absolute first category you pick would be sex, to give access to that 50% of the population.
After that, you can look at age, disability, weight, height categories, but those categories are less productive than sex in that either they open to far fewer people or open to people who have a chance earlier or later in life. Sex categorisation immediately opens up competition to 4 billion people who would otherwise never have a chance at any point in their life.