The forums of all the assorted open source NVR's would also be a good place to share your findings. Zoneminder, Shinobi, Frigate, etc... I mentioned Zoneminder as they are used by a number of corporations and requiring an outbound connection to a 3rd party would be a show stopper for many of them so this topic should be a shared concern.

[1] - https://wiki.zoneminder.com/Hardware_Compatibility_List#IP_C...

[2] - https://forums.zoneminder.com/

[3] - https://www.haproxy.org/

You may need to enable RTSP (https://www.tp-link.com/us/support/faq/2680/) to get a feed off them directly, it works fine in Frigate and any other viewer that can consume RTSP.

I am not defending TP-Link, but it's a pretty big claim for you to say their devices don't work offline and will immediately power down, without any supporting technical evidence.