If memory serves, each cadence and speed sensor has a unique ID number that once paired, is remembered by the device.

When a sensor is active, such as wheel rotating with a speed sensor attached, the device reads that and automatically connects.

Its not dependent on you choosing a particular Activity Profile (from what I’ve seen) and just “knows” you are using a particular sensor set.

Obviously if only certain screens are set in the Activity Profile to not show cadence (as example), you may be getting data but nothing displayed. Thus you still need to change to the Activity that will display data from certain sensors. Speed isn’t one of them, the device will always use a speed sensor data and display that in the speed information.

Garmin did away with Bike Profiles at some point, I had it on an older 810, but they switched to Activity Profiles with my 1000. I renamed a bunch of activities with a bike name - Soma, Stumpjumper, Fuji, Chisel, as example. Different data screens dependent on the bike.