Blue Iris supports RTSP and ONVIF. I have all my cameras setup as RTSP feeds and BI consumes them.
Then I use @bptworld's BI Control app ([RELEASE] BI Control - Local Blue Iris control) to tie HSM modes to BI profiles. For the reverse (using cameras as motion sensors), I have rules setup in RM using the local endpoint trigger and BI sending alerts to that endpoint.
Finally, I have Pushover alert sent and AlexaTTS speak a message whenever one of my cameras gets triggered.
Works a treat!