Yeah, that's great. Aside from the fact you need to invest over $500 in the DM Pro hardware. (I know because I have a DM Pro and four Unifi AP's).
Then you need RTSP compatible cameras, a decent 4TB hard disk designed for camera recordings (WD do one), so add another $200 on top, and then your time. A Unifi camera is about $300-$400 for the lower grade ones. An RTSP compatible camera costs about $150 more or less. My time is over $400 per day, and I see myself doing at least 2 days worth of config, so that's $800. (Nobody ever looks at this). So far, we're at about $1800, maybe more when you add cabling and installation costs.
Ring Protect Plus on the other hand, charges me $100 per year. That's it. I just install (10 mins), configure (20 mins), and it works. The camera costs about $80 each.
However you look at it, the cost is a fraction of what you would pay for a Unifi system. In fact, my mother in law has a Reolink system, which is much cheaper than a Unifi service and it's also RTSP compatible, but for her 6 cameras, 4TB PVR and the installation, she spent about $1,500. I will say the cameras are astonishingly good as they are 4K and the picture is phenomenal, but that's still $1500 vs $480, plus $100 per year. (In that budget you get 10 years subscription).
Short of the long, you get better systems, but the reality is the subscription, really isn't that bad when you put it all into context.