I've been testing PPPoE demand-dial on RRAS role, and it seems like since Server 2012 R2 the issue isn't fixed.
I've found a thread about the issue, and some folks were modifying the DLLs to get it up and running, but I am not sure if the issue persists in Server 2022, does anyone have a clue about that?
The thread -> https://social.technet.microsoft.com/Forums/windowsserver/en-US/b8711a42-99e5-4cff-ac4d-a1d31899a325/windows-server-2012-r2-pppoe-broke-in-rras?forum=winserverPN
It seems like the role is low-key left alone, and nobody hesitates to fix the issue.
Workarounds are not a permanent solution, at least in this case...?