Users connected to my camera

Considering a person just requires the app, an account and the QR code to connect to the camera, this device can be hacked easily. How would I know which all devices are connected to my camera?

I’m not sure if I can answer this question correctly. Now let’s say someone with the eufy app and an account has access to your cameras QR code. Now for them to add your camera to their app, you would need to physically activate / hold down the sync button on your camera. Doing this would / should remove the camera / device from your app.
Unless there’s some other way to bypass this syncing process that I’m not aware of?
I don’t think you can have one camera on two apps unless you are sharing them?
If anyone else has a comment please do Post.