so I ended up having to force a weird circumlocution
Sorry to derail this a little as I’m aware you’re a native speaker, but you did remind me of my interactions with ESL Germans online, where they’d say “Apologies if my English isn’t great; there are gaps in my vernacular” or something wonderfully eloquent like that, that which always comes off as such a casual flex 😆
Having additional virtual network interfaces on VMs is completely normal, ens18 does indeed sound like the right one you should be looking at.
Seconding the other commenter who mentioned the possibility of a second DHCP server.
Is your Proxmox host wired via ethernet to the pfsense? Or are there WiFi APs in the mix anywhere