Having flown CX J and F over a 100 times (say 20 in F), I find significant improvement of F seats over J.
CX F seat is one of my preferred F seat. Very wide at the shoulder,as opposed to most, very private.
With the better wines and spirits of QR F and instant service, I would not hesitate to pay 45k avios for luxury.
BTW: CX had made some retrofit on those F seats. But I don't think that they completed it on all their birds before covid. That could explain the explain the experience differences on these 6 QR exCX birds, which were mostly older ones.