4G back-up internet question

I’m torn between choosing Eufy and Ring for my alarm system and video surveillance. I’m leaning more towards Eufy because I like its cameras, local storage option, and advanced processing capabilities. However, what I find lacking in Eufy is built-in 4G support for internet outages. Now I’m considering getting a 4G dongle with a SIM card, plugged into my router as a backup solution. However, I’m unsure if this setup will work seamlessly with Eufy. Can a wired HomeBase 3 handle the network switch to a 4G connection, even though it’s still physically connected to the same router via cable? Or will changing the network require me to re-set up the devices? Has anyone had experience with this setup?