I have a wireless backup[1] using Vyos[2] and a 5G router provided for free by the 5G service provider for those rare moments when both fiber links are dead.

At the same time I would never recommend anyone get 5G internet as their primary service if you have other options and especially not from one of these cheap providers.

[1] https://sschueller.github.io/posts/wiring-a-home-with-fiber/

[2] https://sschueller.github.io/posts/vyos-router-update/#wan-f...