interesting observation, I am shooting out my window with my R6ii and 100-500 and R7 with RF100-400. I have the focus set the same as far as I know with both cameras but the R6ii is sluggish and often I have to twist the focus ring to get it to focus especially when using 500mm at 25' and then try to get a shot at 10', the R7 with the 100-400 snaps into focus every time!
I thought it might be the lens so swapped them and the R6ii is still sluggish and often takes two pushes of the focus button to focus or never will and have to twist the ring, while the R7 is still snappy even with the 100-500.
Not sure why this is but I have noticed it for some time, the R7 is snappier on focusing.