http://ciisqbg45nggykdl6rjdrq3wc64csga4vkphu66qsi65mypeitqedoad.onion/pfsense
If you want that, go to System -> Routing, then Gateway Groups, then click the Add button. Set the Group Name to Prefer_WG4, OPTGW to Tier 1, and WAN_DHCP to Tier 2, then Save / Apply Changes. 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.