Linux is becoming what Windows was a few years back.
NetworkManager inexplicably dupes a NIC. Makes it Wired Connection 1 and Wired Connection 2. Original is deleted.
Deleted the faux entries and the original one magically reappeared. However, all firewalld rules were missing thus rendering services with WAN connectivity null and void. All masquerading gone. etc.
Mind made up. Will replace this box with a pfSense appliance.