I live at about 7300’. I can spend weeks on my trainer at 7300’ and when I ride at a trail that is about 6000’ my Garmin will tell me I’m adapted to 4000’.
What exactly is your question? Do you want to know whether TR records the altitude of your workouts?
Seems to be a good reason to dual record the rides on your garmin if that data is important to you - TR does not save that info.