We cannot use Incus’ Network Zones feature because we will reuse zones in other Projects. We use BIND’s RPZ feature to optimise traffic based on source IP.
When using OVN networks what should we replace ISC DHCPD + RDNC keys with, to send DDNS updates to BIND severs, or should we disable DHCP in Incus to continue using DDNS & BIND?
You should be able to use the IPAM API to pull all the information from the IP addresses in use within Incus and then update your external system with that.