I think you can make it with plane mesh with uv texture, but the problem is you can also sculpt in there, we don’t have a feature that you can “lock” them; or maybe you can Request A Feature to have an extra gesture slot to act like a switch for a background/reference image edit mode.
For example
Triple tap at the background/reference image
Then it should be able to edit the background/reference image. Something like zomm, pan, etc.