Do Garmin and Apple Fitness play well together?

Hi

I currently use an Apple Watch for tracking all of my activity which is great as tracks outdoor rides and recently my Apple Fitness + workouts and it’s all in one place. Also works with collecting my Vitality points.

I want to get a garmin edge soon with the garmin HR monitor and other sensors (as the Apple Watch won’t transmit HR data to it). I know the data will go straight to Garmin to Vitality, so I’m ok with that.

However what happens when the data transfers to Apple Fitness? As my Apple Watch will be tracking my elevated heart rate, will this add the data together so think I’ve burnt twice the number of calories that I actually have done?

Thanks 😊
Specialized Roubaix Pro Expert 2020
Boardman HT Pro Ltd Ed MTB
Boardman Pro Carbon Road Bike (Turbo Trainer)
Charge Mixer