Can I Use My Phone’s Cellular Data with My Router?

Probably not the best route. It's usually easier to just use your phone as a hotspot. If you're worried about changing settings on all your devices, you can set the same SSID and password on the phone hotspot as your router and then just switch off the router when you need to use your phone's data.

Nope, that setup won't work as you think. The USB tethering feature is limited and your phone won't function as an Ethernet adapter. Your best bet is to set up a hotspot with the same credentials as your home network. That way, when your home internet drops, your devices will connect to the phone's hotspot automatically.

You can actually use a dedicated cellular hotspot connected to your router for a hardwired solution, but it's a bit complicated. If you have a router that supports USB WAN, you might integrate a phone that way, but not all routers have this feature. Consider upgrading to a 5G hotspot for automatic failover if you're facing lots of internet issues.

There are routers that allow multiple internet connections. For example, my Quantum Fiber connection switches to a slower Comcast option when needed, and I could even add a cellphone connection if necessary. Just double-check your router's capabilities.