Given an instance of an HKWorkoutRoute sample, how does one find the HKWorkout that it belongs to?
Finding HKWorkoutRoute's parent HKWorkout
The preferred approach would be to take an HKWorkout and then create a predicate/query to find associated route samples. I don't think it is possible to go the inverse of that.
Check out this link for details: https://developer.apple.com/documentation/healthkit/workouts_and_activity_rings/reading_route_data
Out of curiosity, how are you getting references to your HKWorkoutRoute objects now?