I don't know about that. Yes, the glass bird looks much sharper in the R6m2 pic but looking at the noise in the background and the darker areas, the R5m2 shot looks cleaner to me. And I think you might have missed focus on the bird with the R5m2. Or there was some camera movement. In any case the bar on the right side of the round glass is in better focus than the bird in the R5m2 shot whereas it's exactly the other way around in the R6m2 shot. So focus did not land in the same spot for these two shots.
Also, I don't think you can compare the files from these two cameras like this, as you are comparing 24mpx to 45mpx, that's an unequal playing field. You would need to downscale the R5m2 file to equal the R6m2 or upscale the R6m2 file to equal the R5m2 file.