There is no carrier services in Australia today that run in the mmWave band. Telstra and Vodafone have some 5G coverage in "low band" range (Telstra in the 850MHz band and Vodafone in the 700MHz band). Optus uses 2300MHz and all three telcos have 5G in the 3500MHz band. The Telstra and Vodafone services in the lower bands will provide greater geographic cover, but limited maximum bandwidth per connection.
mmWave (25-39GHz) covers a much lower radial distance from the cell transmitter/receiver (maximum of about 200m), requiring greater number of cells to cover an area. Hence the comment above about needing more fibre to connect these cells. To the best of my knowledge, there are no commercial operational mmWave cells in Australia yet. Expect the initial mmWave deployments to be in very limited geographic spaces where there is demand for high user/device density, such as buildings, stadiums, convention halls etc.
The way we will use mmWave in homes is with high-speed fibre or mid-band cellular to the property and then a local micro-cell in the home providing the mmWave connectivity for all the in-home devices. So you QFF Shop Toaster talking to your KrisShop iPad communicate locally via mmWave, but the external communications is via the NBN fibre or 5G mid-band cellular.
Those lucky enough to get 5G mmWave in their street will likley still have their own mmWave micro-cell in their home with an external antenna on the roof or near a window, because mmWave penetration into buildings will be limited (higher the frequency, lower the wavelength and lower the penetration through dense materials.