This is a pretty interesting claim...I have a few C110 and C200 that work just fine offline after null routing them.

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.