Eero Internet Backup through ethernet connection as well as WIFI

Please can you added the option to use the Eero internet backup feature using a hard wired (second) connection on a eero ethernet port. 

 This surely can't be to difficult to add as you already have the option through wireless within the Eero app. 

If I plugged for example a 4g/5g modem into my upstairs eero ethernet port this could be used as a back up to my normal fibre connection if it ever goes down.