On a quick EF check for Tuesday 18 May 2021,:
ZL's 0700 hours MEL - SYD had 92 in whY, the 1000 surprisingly fewer with 54 and the 1200 'high noon' 74.
Southbound, the 0700 hours conveyed 46 in whY, the 0-930 hours 88 and the 1300 hours (very much off peak) 63.
The one QFd flight I checked at 0700 hours MEL-SYD was a widebody, A332 VH-EBK, but while better loaded than ZL (and way better in yield), it had many empty whY seats. QF's overheads are way higher than Zl's will ever be. Three years ago, even on a Tuesday (usually it and Wed are the quietest weekdays), it'd have been likely that QFd's 0700 would have had 95 per cent of seats occupied (with the vacant ones largely being non shows).
I didn't check J passenger numbers on any of these so in most cases the true number of revenue passengers would be higher.