In some places you can get a home internet line that runs through the mobile phone data network, and they tend to be more reliable than cabled connections, they can get even better if they use a modem data plan and not explicitly a home bulk plan. It really hinges on how much data you use and what plans are available where you are. Of course if you do it this way you won't have a private IPV4, but if your ISP allows IPV6, that should be unique and directly accessible no matter what.

As the other poster mentioned there are routers that have a SIM connection as backup, and now they're being offered with a SIM and automatic fail-over as part of some fiber to the home plans.