Thanks for your query.
Currently, we do not have any lists of WiFi 6 modems compatible for our TPG FTTB service, but will raise this to our team in order to make one in the future.
In purchasing a third party device, please be advised that the phone service will not work if you are under our bundled service plan (Phone and Internet).
If you don't use the phone service, then you just need to look for a device that can be configured with VLAN ID 2 and PPPoE connection type.
That's the main configuration that a third party modem/router have for it to work with our service.