The issue is you are trusting these camera companies (mainly Chinese) to implement proper security controls and they have shown time and time again they can't be trusted to do so. Who knows how they have programmed the P2P function "behind the scenes". That is reason enough never to port forward directly to a camera in my mind.
Many brands like nest, ring, etc do not allow you to store your video locally. You scan the qr code to enable the p2p and you are up and running. Weeks or months of your footage are in China or wherever.
Never allow your cameras direct access to the internet. It is not the video that is the problem, they are on your home network monitoring what is going on. Please send your bank accounts, files, passwords directly to china.
Don't port-forward for direct camera feeds. It's fine to port-forward to security devices. Like a VPN gateway. See here: Noob Question on Router & Switch