PPPOE Security

I hope this is the correct place to ask this. We firstly need a “PPPOE credentials” to connect to a service provider (ISP) and then its connects to a modem and then finally to a router, then lastly internet is provided to devices. My question is. Let’s say someone somehow gets a hold of the PPPOE login credentials (which the password is only changeable upon request to the ISP provider), can they (the hacker or whoever that has the PPPOE login credentials) hack into our internet traffic such as connected devices, access our pc or devices connected or access our router? Thanks in advance boys!