Multi-WAN with many local interfaces: For the shaper: What counts as what?

[demux]

Hi,

I would like to set up VoIP priorization/traffic shaping but I do not exactly know which interfaces fall in which category and how to count them. I will use PRIQ.

I have 2 WANs with static IPs.
And an additional LTE connection as backup.
For VoIP all interfaces are set up as failover with LTE as least priority.
Other traffic will only use the WAN interfaces in failover mode.

There is one physical LAN interface with 3 VLANS. One of the VLANs is dedicated to VoIP and got the PBX and the phones. One is for the devices (IoT), one is for public access and "last one VLAN (id 1)" is for the rest.

There is one other physical interface with 3 VLANs that serves as a DMZ, directly connected to a machine with 3 virtual machines.

There is a Wireguard server running and there is an OpenVPN server running (both incoming).

And there is an OpenVPN client running connected to an OpenVPN server but only machines out of a specific IP range on LAN are routed through this connection.

How do I count LAN and WAN interfaces for the traffic shaping wizard?

Thanks!
-demux