Asking here as not got much response elsewhere and aware a lot of UK MSPs use Draytek's. I have a Draytek router install (usually use FortiNet but its ad-hoc work), so I am on the Draytek website testing the Draytek demo interface.

I am trying to create 2 VLANs (office & guest) and have them use different WANs because the broadband speed is very slow so guests need to be on the 4G network. But have a few questions for those experienced with Drayteks.......

Is this route policy / load policy correct to point VLAN 10 (office) to WAN 1 with a failover of WAN2 ?? I was expecting a way to select VLAN ID rather than just put in the IP range?

The Draytek will have a Managed Ubiquiti Switch & Ubiquiti Access Points. When setting up FortiNet you set untagged VLANs to a port on the firewall. How do you do this in Draytek? So that all VLANs passthrough the port then the AP manages the VLAN by tags?

Why bother with guest WiFi if it's 4G anyway?

Re VLAN tagging. Consider that VLANs are a layer-2 construct and that the Draytek is a router and a switch combined. The VLAN tagging is defined under LAN, VLAN, which enables the configuration of the IP Subnets (e.g. LAN 10, the IP address space associated with that) to layer-2 VLANs (assume VLAN 10 for convenience). Then define whether it's tagged on not. Assuming you did VLAN 10 untagged and VLAN (11, Guest?) as tagged, then the Unifi switch uplink - and associated UAP configs - should be done the same as well.