Not quite that but I ordered an Eaton 3S 850, which is a beefy power strip with built-in battery and looks like a decent compromise for cases where you don't really need a huge noisy rack-mounted UPS, but something that can do a bit more than just a Raspberry Pi (i.e. several Pis plus the router).
But would you only need 5V? DSLAMs here have an hour or so of UPS capacity as well, so if the router stays up, so does the internet connection, same with 4G/5G routers. Though I guess a 5/12/24V DC mini-UPS would still be a lot easier than actual 110/220V AC.
