The PPPoE docs for Eero say you need to go into the app settings. The app settings aren't available without a device already set up. So how am I supposed to set up my Eero with PPPoE? Weird chicken/egg dependency there.
I set my Eero's up the other day with my PPPOE provider with no problem. As you progress through the setup it will fail and you will see a manually configure internet settings option become available. You then choose the connection type PPPOE.