Sorry it's an old topic, but still relevant today and unanswered. Also high in the search results.

Reolink should indeed do a better job explaining their "UID" mechanism / P2P system. Which is actually contacting the Amazon cloud. Using a technique called "hole punching" through the firewall, without the users knowing.

This is very dangerous, so you should ideally put your camera within a separate VLAN. Reolink, please just be more transparent about your products.

Another option I found is to basically disable P2P by unchecking "Enable UID" within: Settings-> Network Settings -> Advanced -> Enable UID.

After more searching, I finally found this article from Reolink: https://reolink.com/blog/p2p-ip-camera/

@Reolink If I disabled UID feature, can I still enable port forwarding manually when needed, giving back control to the users? Which port should I then forward manually to keep using your mobile app?

Hint; search on Google: "Peer-to-Peer Functionality in IoT Security Cameras and Its Security Implications"