Honestly it might be less work than some other cameras that (allegedly) speak RTSP. You'd be shocked how low-quality these implementations are. Never advancing timestamps, setting the RTP MARK bit arbitrarily, writing uninitialized memory framed as audio packets (on cameras that don't have microphones), closing file descriptors then writing data to them anyway (and so having it show up on the next accepted connection to be assigned that fd even pre-auth), etc.
Thanks for the reassurance that I'm not such an incompetent dev as I feel.
Funny how companies tend to be competent at either devices or software, and rarely both. This sounds vaguely like the automotive industry.
https://www.arecontvision.com/news/arecont-vision-adds-casin...
(eBay deal sniping sometimes gets you some funny deals but YMMV — I picked up an Axis Q1700-LE license plate camera for under $200 for some experiments.)
Vivotek's a bit more reasonable but still. The (brand new?) Vivotek VIT04A-W is the closest I've found—1/1.8" sensor, 4MP, turret, $535 on jmac.com.
These Ubiquiti models seem really nice in terms of hardware specs and and very reasonably priced. $200 for a 1/1.8" sensor turret, $479 for a 1/1.2" sensor turret with extra AI features. Same general price bracket as Dahua, I think.