http://ciisqbg45nggykdl6rjdrq3wc64csga4vkphu66qsi65mypeitqedoad.onion/pfsense
If using IPv6, add another Gateway Group, with the Group Name set to Prefer_WG6, OPTGWv6 to Tier 1, and WAN_DHCPv6 to Tier 2, then Save / Apply Changes. Go back to System -> Routing, then change the Default gateway IPv4 to Prefer_WG4, and for IPv6 to Prefer_WG6.