Uplink balancing with a faulty uplink

Hey this is my first post. I'm sitting in germany using vodafone cable and as this is often stopping to work I bought a backup 4g router yesterday and connected it. I connected the router to the UTM...
WAN FAILOVER DUAL CONNECTION

I have a Sophos UTM9 cluster where each firewall is connected to two different ISPs (let’s call them WAN1 for Provider A and WAN2 for Provider B). Let’s name the interfaces 1-2 (node 1) and 3-4 (node 2...