well this is a good start
so if I read this correctly,
the enp4s0 and enp1s0f0 should be plugged in into a main switch for LAN.
enp1s0f1 should be connected to your ISP modem/router.
we can easily ignore vmbr2 as it is the outside connection and managed via pfSense.
so the important information that is missing is your pfSense LAN IP.
but let's assume it is 192.168.1.1
than in your proxmox network setup you would configure
#1. default gateway pointing to your pfSense LAN IP (192.168.1.1)
and assuming your pfSense also serves as DHCP server and Domain Name server (DNS)
you would point your DNS to same IP (192.168.1.1) and you can also add additional DNS pointing to the IP provided by your ISP and I also add a google IP like 8.8.8.8 and/or 8.8.4.4. you do not actually need to do that in local network setup. the pfSense should do all the translations for you. and if you use DHCP on pfSense it will also do that.
so you point to pfsense as both a gateway/firewall, DHCP and DNS in all your setups.
just FYI, you need an internal DNS IP (192.168.1.1) to resolve any and all internal name. so any physical machine or VM inside the LAN can only be resolved by the local DNS server i.e. your pfSense.
all external URL/IP references are resolved by the external DNS such as your ISP or Google.
the steps are your Client calls for a name/URL == > request goes to local DNS first ==> if no exists forward to next DNS server on the list (hence the need/preference to have several ) ==> if found open the address, if not show error.
so your pfSense should handle all DNS needs you have using any and all DNS in the list.
I, personally is moving away from static IPs on my network with a single exception of the main Host.
some physical and VM machines simply need to be static. any others I am trying to go with DHCP reserved IPs.
that is I find the NIC MAC address and setup a reserved IP in DHCP server to always give that specific IP to that specific hardware NIC. since in VM I can control the MAC address I use it works well.