MacKungFu:

If you open an app you normally use with AirPods, your iPhone or iPad will automatically connect to your AirPods if they’re in your ears – essentially, “stealing” them from whatever they’re currently connected to (for example, your Mac). No need to manually select and connect to them!

This process requires a bit of Shortcuts work. But the steps are very well laid out. A fun project, if you’ve got some time on your hands.