This must be fixed, I'm sure others have issues with this, its taken me several months to get to the point where I post this, its been happening for way too long. No matter what Bluetooth device is connected the volume bar is always on the top of the screen. I recently bought a Galaxy Active2 watch so now its up there ALL the TIME. I can't see the clock, I struggle to touch the notification bar, its all blocked by the sound bar. It doesn't matter whether its my car, my watch, or my portable speaker, all Bluetooth devices seem to cause this problem. At first it was just an annoyance here and there, while in the car, etc. Now having this watch connected 24 / 7 its all the time. Please get a fix for this.
Have you tried clearing system cache or safe mode
System cache: power off your device and press and hold volume up bixby and power till you see the Samsung screen, when the recovery menu pops up use volume and power buttons to select wipe cache partition. Select Restart your device.
Safe mode: press power till you see power off, press and hold power off till you see safe mode
If this doesn't help you might want to consider a factory reset after you back up all the data on your device.
Hope this helps