The only issue with the schemes mentioned below is that if you care about Garmin performance metrics then they say they only include rides captured on a Garmin device. So, if you want indoor rides to count into the Gamin metrics then you need to record indoor rides on your Garmin computer as well as in TR. hen you get duplicates. If you don’t care about Garmin metrics then the methods mentioned in this thread work fine.
For now I record all of my rides (indoor and outdoor) on a Garmin device. This results in duplicates in TP and Strava. They only take 15 seconds to delete so that works fine for me.