Can you stop someone mirroring your phone?
Disable mirroring
The functionality is called something different on various Android devices. In Samsung phones, it's called Smart View. Go to the setting in your phone, and you'll see any devices that you may connect to. Ensure no devices are mirroring your phone.
How do I block someone from screen mirroring?
Step 1: Find and open Settings on the device. Step 2: Type screen cast in the search bar and then search it. Step 3: Click Cast from search results to continue. Step 4: Disconnect any devices listed in connection for screen mirroring.