Yes, but with restrictions in events like the Olympics

If the athletic event isn’t separated by sex then trans people have every right to participate.
For events such as the olympics, if the trans athletes started their transition at an early stage in their life then their body should have the same physical abilities as the athletes they are competing with. If their transition occurred after puberty or recent to the event they want to compete in, then it would be an unfair event.
Forcing trans athletes to compete according to their birth assigned sex would also be unfair because of how hormone treatment affects their bodies. Trans women lose muscle mass and would not be as strong as a man. Trans men gain muscle mass and would have an unfair advantage when competing against women.