Having done the 3 QF linked lounges, ...
EK MEL one is the best, salmon, yep, salmon for breakfast (this was pre covid of course, when EK still flew MEL - AKL in the 380 with an F service).
QFi MEL F lounge, very good, no runway views, as it faces the parking bays.
QFi MEL J lounge, is in basement, good for a one look see what its all about, but no outside views, as its on ground level, and maybe they are afraid some "muppet" might break the glass windows to get onto the tarmac, so its all enclosed, with no outside views, not sure what is on the other side of that exterior wall with no windows.
Quite dark and gloomy, really, mind you, its lit, but without any outside light, its not the best time to spend too much time in there.
Haven't done the Maharba, so can't say about that one.
No harm for you to go through immi and int security at 7.30pm, and go to the QFi MEL J lounge, just to see what it looks like, if you haven't been in there before.
Its (the QFi MEL J lounge) is also a bit hard to find, as its no way near the location of the QFi MEL F lounge, or the EK lounge.
Edit: if you want to try the QFi MEL J lounge, go to the middle of "Hospitality", where there are several shops, around gate 3/4/5..6/8/9, if you go up to level 3, its the Maharba and QFi MEL F lounge, but the QFi MEL J lounge is no where near this, its on ground level, so you have to get the lift down to it.
From dep gate level, you can get the escalators up to level 3, where the Maharba is and the QFi MEL F lounge is.