I don’t know how useful this would be for others but I think it might. We have the soho mk3. We are a restaurant and have a dedicated mobile phone usb tethered as backup internet. I separated vlans/networks like, private lan, public wifi, employee wifi, smart devices, etc. When the gateway fails over to the mobile phone, I manually go into my AP and disable the Public Wifi and Employee Wifi so as to save the limited high speed data available on that plan. I think it would be pretty useful to add a feature to automate this. Something like, if network = priority 2 → disable vlans Pub Wifi, Employee wifi. Upon failing back, these networks would be reenabled.
Just an idea. I think it would be sweet.