Brian, why does it matter if your public IP address changes, that won't affect the local LAN IP addresses the DHCP issues? Or are your ESP32s on a WAN or connected to the internet themselves?
Took a look at the Draytek and interestingly enough it actually seems to have a built in DNS on the LAN side, so I'm assuming you can create domains on your LAN (nice), that is probably why those routers are at least $100 USD more than most of the home routers you find. They seem to have a lot of business features on even their "connected home" line.