There was an interesting documentary I caught on the BBC recently about Paralympic sport and problems with the classification system that separates disabled athletes by conditions/equivalent ability and how hard it is to keep it fair. "The Unfair Games"
At first I had an exposé saying that one type of decision was wrong but it would then talk to the supposed beneficiaries of that decision and you'd see it had wrecked their sporting careers too.
Seeing how even small changes to a category or to an individual's classification could deeply affect the fairness of a race and the knock on effect to people's careers, funding etc.
It's not about trans sport, but it does raise similar issues about level playing fields and how changes like this are exploitable and the pressures and prestige around countries trying to get more medals. And how if a classification is widened to allow more able people into it then it quickly disadvantages the people the classification was originally for.
I think if you have enough trans people interested in elite level sport you could try and create a classification system to allow inclusion and fair competition, but it would have to account for biology and wouldn't be males competing against females.