@Khoomn Proxomx management port needs to be connected to your lan.
If you are using pass through for the pfsense NIC that will need to be done by connecting a third NIC on your Proxmox box to your physical network switch.
If you are connecting the pfsense VM to virtual NICs then you will be connecting each virtual NIC to a bridge (software switch) in Proxmox. You can then connect your Proxmox management interface to the LAN virtual switch (define an IP address for it in the Proxmox network tab)