Why can't I get 4G on my brand new iPhone 8 when I'm in South Brisbane? In fact, I seem to get more 3G reception than 4G in a lot of places in Brisbane when there is supposed to be a 4G Plus service here.
I go through South Brisbane on my Train every day and never had an issue today.
Is a few towers being upgraded in west end - but having little to no 4g - soemthing isnt right.
I would suggest a reset of network settings.
Also make sure that 4g is enabled on your devices network page (my iPhone 6s had that toggle, no idea if that remains in later devices?)
If you still have issues I would suggest a sim replacement via an Optus store (Queen Street, Brisbane CBD would be your closest)