Yeah I think there's a natural feeling to pour cold water on Sarr because tall poppy syndrome. But Bissouma form has fluctuated too much to claim he is more important than Sarr. But in my honest opinion its been harder to replace what Sarr gives us than either Bentancur or Bissouma. This maybe credit to Hojbjerg and Locelso more than anything else, but him being out has hurt more. I don't really count Madders because I think he is purely an attacking player.I understand what you mean.
But Bissouma has been VERY hit and miss. Plus mostly due to his own genius choices, he has not been there for the team for part of the season. With Madders it was the injury that kept him out and then it also has taken him time to get back into form as well.
At the same time, Sarr has been almost always available (bar AFCON) and has consistently been brilliant.
I also agree in the sense that it is hard to compare them, #6 is such an integral part of the Ange-system, so purely that fact plays to Bissouma's hands. But watching back the whole season so far, #6 is also position I am mostly concerned of and needs attention in the window. PEH will move on and we need to bring on another specialist to that position.