No issue getting into SYD on arrival yesterday at approx 5:30pm.
They were scanning all BPs and a roaming staff member moved along the queue asking everyone to check in with the ServiceNSW app. Must have been about 25 people trying to enter, the queue stretched almost to the top of the escalator.
On reaching the desk I flashed my Qantas app BP and said "arrivals access". They mustn't have heard clearly through my mask and their perspex panel as they gestured for me to scan the BP, then said "no that's your boarding pass from Melbourne, scan the BP for your onward flight". Said arrivals access again, a little louder, and they asked to sight my Service NSW app check-in and let me in.
It was quite difficult to find a seat, the only open spaces were the stools right around the back. The lounge was full enough that declining arrivals access based on capacity would have been fair.