Using non-ring cameras with Ring Protect Plus

Hey everyone! My wife and I are planning to get a ring alarm security kit and hook it up with Ring Protect Plus and want to add a few cameras as well but have a question about using non-ring cameras with this. Basically, can we? Or does the app/controller etc only work with ring cameras? I tried searching through the forums here for an answer but didn't have luck. Thanks for the help! Cody