@jknott
The packet capture via mac address is a good idea. If I decide to create an IPv6 table for my local devices, I'll use it.
Regarding routing, I realized that I have to add a route for ULA devices if I don't create an address for the interface itself. It's for devices on a different VLAN to reach ULA devices (admin to IOT).
Anyway, thanks for your insights. Learning and deploying IPv6 has been pretty time consuming, I got to catch up with my real life!
Thanks,
Devan