I might have something for this. That said, it is important to note that most canon Riders are able to consistently fly with their mounts, and flight is only really an issue if the Rider possesses the skills of an Archer, which uhh... most don't. They don't need to have wings to fly around, after all. What balances them in combat is how mounts don't possess the same amount of burst speeds Servants do. It'd be like trying to dodge things with Torrent's dash on Elden Ring as opposed to rolling around~