I want to add a term that I haven't seen in this discussion so far. IP cameras can interoperate with Open Standard NVR systems using ONVIF. [0]
ONVIF cameras, or cameras that support ONVIF are capable of communicating settings and streaming video to recording servers without intermediaries. RTSP or MJPEG are available as media layers ( not the only ones, but ones called out so far in the conversation as desirable for viewing and recording), but the ONVIF configuration makes this easier.
Looking for ONVIF cameras will help you find cameras that might not NEED the app for full functionality use even though, like Reolink, they may offer one. The NVR is the appropriate "glue" for those app functions.
Examples of ONVIF NVRs are not rare, but self-hostable, and free to try or use at some scale are hard to find. These are often the Big Boys. Milestone XProtect, Senstar [ Aimetis] Symphony, but also more DIY options like iSpy, Blueiris, and things in the middle, like Orchid from IPConfigure [1] that you can run on a Raspberry Pi at a small scale, or a Hybrid Cloud setup for enterprise use.
I've done this a lot, it has worked with every ONVIF capable camera I have tried. It is sometimes a real nightmare to figure out the stream location and video settings though.
Additionally, Amcrest sells ONVIF compatible cameras that do have a web UI and can connect to any of those NVRs, or a wide number of ONVIF viewer apps on any device you want. They're a bit more expensive, but still dirt cheap compared to more reputable brands mentioned in this thread.
ONVIF cameras, or cameras that support ONVIF are capable of communicating settings and streaming video to recording servers without intermediaries. RTSP or MJPEG are available as media layers ( not the only ones, but ones called out so far in the conversation as desirable for viewing and recording), but the ONVIF configuration makes this easier.
Looking for ONVIF cameras will help you find cameras that might not NEED the app for full functionality use even though, like Reolink, they may offer one. The NVR is the appropriate "glue" for those app functions.
Examples of ONVIF NVRs are not rare, but self-hostable, and free to try or use at some scale are hard to find. These are often the Big Boys. Milestone XProtect, Senstar [ Aimetis] Symphony, but also more DIY options like iSpy, Blueiris, and things in the middle, like Orchid from IPConfigure [1] that you can run on a Raspberry Pi at a small scale, or a Hybrid Cloud setup for enterprise use.
[0] - https://en.wikipedia.org/wiki/ONVIF [1] - https://www.ipconfigure.com/