In my experience pretty much all IP cameras phone home in some way at some point, so yeah, you are best off putting them on a separate VLAN and routing appropriately.

The only brand I’ve had a good experience with is Reolink. I don’t think the quality is appreciably different than a brand like Hikvision and the firmware and support is vastly superior.

Edit: Some good info on using Reolink cameras with Frigate. I use Blue Iris but would vastly prefer OSS.