a surfacegui in startergui with the adornee set to the mirror part so the surfacegui is displayed independently from every client
a viewport frame inside the surfacegui that covers up the whole thing
a camera inside the viewport frame that follows the player humanoidrootpart but at the opposite direction from the mirror. so for example: player is at -5,0,0. mirror is at 0,0,0. that means that the camera inside the viewportframe is at 5,0,0.
the problem is that the camera could only “record” one part instead of all parts in workspace right?
I’ve seen this work somewhere before. Last time I used a similar model which was a viewport camera, and it showed my character and every object behind me in a monitor.
I can refer you to this post, as this may assist you with what you’re asking.
a better idea that would probably be more optimized is to just have a different room that’s just copy and pasted level geometry with a roblox figure inside, matched to your character’s avatar, walking to your specific character movements ingame