A time ago I remade the ATP Tour calendar 2021 oriented specifically to Challenger Tour, i mean, I modified the ATP tour's ini file where you can find each tournament ATP and Challenger and I added the right names of the Challenger courts, and of course the courts in jpg format to the game too. The idea would be that someone create a mod, as Sammoder have made it before, and after include these courts to it. I can tell that soon I'll share my creation to the community.
Note: By the way, I've been working with TE4, so the courts were made for that version of the game.
Greetings.