@drodgers Hey. I'm going through this exact thing now with Vodafone and pfSense and struggling. I've replicated your settings but it seems very intermittent.
My clients get ipv6 addresses and can ping out fine however browsing this forums dies because it responds with and ipv6 address.
For some reason as soon as I enable ipv6 netflix and paramount also stop streaming 🤦 They browse fine but as soon as you try to play a video it's a no go.
Any ideas or pointers please or could you post your most recent working config please?