Turn off Samsung's Quick Measure from the Camera AR Zone.
But it should only be visible when the Camera is open & running the AR Zone Quick Measure.
If it's appearing on all screens, even when the camera app is closed, I think that you may want to reset the camera settings.. it shouldn't be on the phone's screen all the time.
You could try to Uninstall Quick Measure, (or see if you can disable it) because that looks like the app that is causing the issue.
Wiping Cache from Recovery might help, but if Uninstalling Quick Measure & Wiping Cache doesn't fix it, then I'd backup with Smart Switch & Factory Reset your device.
Lol... this must be the third post I encounter with this "issue"...
That button is the new accessibility button that comes with Android 12. It can be dragged around the screen. But you can also disable it or add more functions.
To disable it, go into your settings, scroll down to accessibility and go into advanced settings.
Click on accessibility button, then click on select actions and uncheck everything.
If this solution has worked for you, please click on the dots next to my post and "accept solution" so that if others come into this post with the same issue, they can easily find the fix :)
I have to admit... that screenshot wasn't the best to show what you meant lol. It seemed more like you were trying to show an issue with the camera.
