The NRL is most likely leading the ratings viewing by average audience. It has done most of the last decade. Ive written about this annually since 2018.
The truth is that it depends what you want out of the ratings.
@docbrown has posted some fairly insightful commentary on this. We are all but poorly informed amateurs trying to make sense out of something that is far from black and white.
The issue comes down to whether you believe that the average audiences are the be all and end all (as is the predominant case here), whether you believe Reach is a fairer measure (as is the case with certain people on Bigfooty) or whether you believe Metro ratings are the most valuable part of the ratings (as seems to be believed by the media and according to recent reports, broadcasters - see article i posted here not long ago), or whether you believe in the Fox ratings (which even Fox dont believe).
All we have is the publicly released data, which this year has more holes in it than swiss cheese.