Zoneminder is a pretty solid setup for IP security cameras, and the zmninja app is really nice too. I had tried it years ago but got back to it recently with some sketchy IP cameras. I just put them in their own VLAN, no Internet access, Zoneminder does motion detection and event recording, and so far I’m quite pleased with it.
I ran ZoneMinder for years before buying a Reolink NVM and now I couldn’t be happier. I’m a huge self-host-er but unless you want to babysit it ZoneMinder is a pain to self host. I ran it in docker, I ran it on raw metal, I tried multiple plugins/configs. Nothing beat the plug and play of a Reolink NVM. I say this as someone with multiple servers and ~150TB of storage locally.
Skip the headache and buy something off the shelf for this.