Started getting email ads for Frontier’s “Unbreakable Wi-Fi” in my market.
https://frontier.com/shop/internet/unbreakable
It appears to be a backup cellular internet service that “automatically turns on” when your network connection goes down. Price appears to be $25 a month. It apparently connects to the Eero so it can be activated when the landline internet through the Eero goes down. Apparently the plan includes 130GB of data per month. See the link above for several FAQ entries.
Setup instructions: https://frontier.com/helpcenter/internet/install-unbreakable-wifi