I am using an OPNSense Router/Firewall and just copied the PPPoE info from the Nokia UX; I have not had a problem in 2 years.
My Nokia Router is in the cupboard since day 1 - they did not want to give me credit for giving it back.
Back to a Metrofibre question:
I have had a Metrofibre 1G/500Mbps line installed - All go after it was provisioned.
I have the Calix GigaPoint 803G ONT adn a supplied Nokia Wifi Beacon 2 router.
Measurements:
ONT to Opnsense Router with with a PPPoE connection - 650Mbps down
ONT directly...