Apple watch Ultra - Treadmill session

Hi, I recently bought the new Apple watch Ultra, I'm an Elite triathlete so part of my sessions are on the treadmill. the accurate on the treadmill with this watch is TERRIBLE, it's like not connected to my real speed, but that it's ok because it can never be accurate on the treadmill. even Garmin and wahoo has kind of bad accuracy. but for sure not like the Apple Watch. the only thing I don't understand, in the other running watches at the end of the session on the treadmill the watch ask you to Calibrate the distance you actually ran and this is how he can understand the pace, so the session upload to Trainingpeaks correctly. at the Apple Watch it doesn't ask me and I can't edit the distance which is terrible because it upload even to my activities false data!

please tell me there is something I missing here, because this suppose to be a watch for extreme athletes and this is a basic feature for running watch today.

I would appreciate any insights regarding this issue :)

Thanks