After running a mikrotik router for a long time and fighting with the IPv6 configuration, I gave up this week and started using pfSense as a test. Within about half an hour (after figuring out the USB boot option wasn’t possible with my machine) I was up and running better than ever!

WAN interface config

General Configuration

IPv6 Configuration Type: DHCP6

DHCP6 Client Configuration section

Advanced Configuration: not needed
Use IPv4 connectivity as parent interface: enabled
Request only an IPv6 prefix: enabled
DHCPv6 Prefix Delegation size: 56
Send IPv6 prefix hint: enabled
Debug: disabled
Do not wait for a RA: disabled
Do not allow PD/Address release: disabled

LAN Interface Configuration

General Configuration

IPv6 Configuration Type: Track Interface

Track IPv6 Interface

IPv6 Interface: WAN
IPv6 Prefix ID: 0 (default)