I used a similar system OpenHAB for “automation” and to view my cameras at first but ended up Just accessing them directly. My issue was video delay through OpenHAB. I used a SANNCE setup because I needed 8 cameras and it fit the bill. Local storage, cheap, no internet access required. It does support a few protocols that any of the big home “automation” systems have support for.
I block the device from getting out to the internet with a firewall rule. Their app doesn’t require registration with the cloud services and I have a split tunnel VPN to connect remotely.
Why would a company provide a free service like a proxy?
I wouldn’t trust any company that claimed they did.