I assume you’ve already searched the forums, but perhaps you could be more specific in where existing threads aren’t adressing your considerations?
For a thread on security cameras, there’s this one: Self-Hosted CCTV (IP Home Security Camera) System
For another thread on security cameras, there’s this: Security camera setup for beginners?
(And for a comment speaking to the reoccurence of this topic, linking to both the threads above, here’s that as well: It's Time to Take Down your Smart Cameras - Benn Jordan - #3 by beantaco )
A generic PoE camera separated via VLAN and accessed via NVR appears to be the most common recommendation, as per this comment, but does that break with your wish for a “reasonable” alternative?