Single PoE switch with cameras on a VLAN (so they don't have internet access). I use my old framework main board (yay for reuse!). Started with a USB Coral but switched to NVMe, which is more reliable passing through to a VM.

Frigate links some Dahua camera recommendations in their documentation: https://docs.frigate.video/frigate/hardware/

I installed them and they've been rock solid. Low light performance is excellent. The turret form factor is nice and unobtrusive.