I ride 3 bikes (not at the same time). All 3 bikes have Speed, Power/Cadence & Di2 sensors paired to the 1050. I also have several HR monitors all paired. The 1050 finds and uses whichever sensors I've chosen to bring along on that ride.
Why assign sensors to profiles, I don't understand the purpose? Can you please explain.
I think the OP wants to automatically assign a bike to the activity in Garmin Connect based on the sensors used, so unrelated to the activity profile, more to do with gear used.
I also use ActivityFix to do the same thing in Strava.
