I don't think any of these AC devices are true UPSes. You can use the more expensive ones as that but likely they won't last as long, the UPS functionality is half baked, they're really sold as emergency or camping power supplies. If you look on Anker's
website, "UPS" does not appear in the product description nor in the manual and it's not stated the device may be plugged in 24/7/365. The Wibox with the replaceable Bluenova is a 104 Wh product which may have more charge cycles (>5000) at 50% DOD, which powering a router/ONT will likely not use more than 50Wh, I think my TP-LINK router uses 3-4 Watts. I think these low voltage DC devices are true UPS devices. Granted the Anker and Ecoflow have 5 year warranties but that may also depend on the dealer whether they honour these devices being used in an always connected way, which is not what they're really advertised to be used as.
My point about the ATS was that they're bundling them because people are using them for what they're not intended to be used for, to be always plugged in as a UPS device. Ecoflow are probably having many returns as evidenced by the refurbished devices they're selling. Anker will probably fare no better, they have access to the same Chinese parts Ecoflow have.
If these devices could be used as plugged in 24/7, they'd be advertised as such on their manufacturer's websites.