https://youtu.be/ETo_ceQvDOs
In this video they tear the phone down. The volume flex is on the mid frame. So,sadly,yes it does require the battery and logic board to come out. It’s a lengthy repair. If you guys attempt this,be ABSOLUTELY sure to keep track of the screws and their holes. Long screw damage is something many repair shops have happen(not saying it will to you. I’m just trying to give you a heads up).
But it requires practically the whole phone to be completely disassembled. Then you have to replace the battery adhesive tabs too.