Let's say I have two connectione, one to my TV and one to my phone. There is afaik no way to manually tell the app/the headphones which input to use without disconnecting from one of the sources.
I have the xm4 ear buds, I can goto my Bluetooth device list and select it from any device. It'll switch to the device without any hassle.
It also supports two device but that's not a good experience.
My xm3 headphones have a single connection issue, but I mostly avoid it using my phone NFC. It prioritizes the NFC contact over any other Bluetooth device. And disconnecting is also just a tap away, easier than going into menus.