Hi All, looking to connect my 4g router to existing Internet setup so that if the physical cable is cut or main Internet is down the 4g will takeover. Main reason is security (because ring does not let you select a second backup network) + control of heating when away.

The main router is a Vodafone broadband hub, I also have a huawei 4g router, a tp link deco wifi network, and an Asus WiFi router (currently unused and may not be necessary).

How would I go about connecting all of this so that the if the main Vodafone fibre connection went down the 4g would take over (ideally on same network) and all connected devices would still work?

Thanks!