Is there still no way to assign a bike to an activity profile?
Garmin could easily do it by allowing assigning a default bike to an activity profile (mountain bike for 'mountain biking' activity profile, etc..), or based on sensors utilized during the ride (AXS shifters, power meter, cadence, etc..) and allowing the user to select which sensors belong to which bike (or even automatically learn it based on prior rides, which would be trivial). SRAM AXS app does it.