So much this. I stopped using my Bluetooth headphones because they would connect while still inside the charging box (after done with charging). Super annoying and they'd run out of battery if I didn't make sure to check if they had unloaded themselves from staying connected. Maybe crappy headphones design but the issue never happened when I manually unpaired them.
I've got another gripe with the bluetooth stack on android: there is no order of device to send telephony to. I never want to listen to music or answer the phone calls on my smartwatch whenever the car or the earbuds are switched off. But i still want to be able to pick up an emergency call from it whenever both are not connected. Puting in a priority order, within which the phone would be, could allow me to make and pick calls from any devices while automatically switching to the phone when the two other forementioned devices switch off.