My 2 cents ....
I've been on Orcon Gig Fibre for about 3 years now. Its great.
The issued router was a Fritz!Box 7490.
I turned off its WiFi and bought 2 UniFi Access Points, UAP-AC-PRO
WiFi speeds are great and stable now with no dead zones in our 2 story timber house.
I also just last weekend replaced the FritzBox with a UniFi Security Gateway (USG).
And moved the FritzBox to be behind the USG.
Our home phone that goes through the FritzBox still works.
Set the UniFi Network WAN settings to:
WAN settings found by searching for this on Orcon's website "Setting up a non-Orcon modem"