Yeah, I had considered this! But, then I'd need a UPS on my modem and wifi, and at that point it seemed overkill.
Although you could use a backup USB cellular modem, plugged directly into the Mac!
At some I imagine I'll inherit or acquire a cheap older M1 Macbook Air, which will be perfect!
I also have whole home battery backup and solar, so I technically have a UPS for everything!
Where I live the power tends to go out from time to time!
I monkeyed around with cheap ex-lease Dell Micro PCs with Intel 8th Gen to 11th Gen CPUs. But they not as performant as I'd like, and once you've experienced modern CPUs like Apple's M series, you dont really want to go back!