I got a lot of those Wyze (Xaoumi) box cameras from Microcenter super super cheap open box. I loaded some custom firmware to them added dedicated access points and a private network, and used BlueIris at my last place. Worked great when it worked.

They are still super easy to hijack though. Since it's just a wild rtsp stream, proximity, some scripts and your neighbors can (pretty far ones if you live in the sticks) can spy on them. Had a buddy who was a real life hacker-man send me a picture of him watching the front of our house from his car parked in the next neighborhood just to prove a point XD