I don’t think you can just isolate it like that. If you don’t have the grip/df on the rear axle then you HAVE to balance it with the appropriate df level of the front wing. Potentially they’ve solved front issues with the altered suspension layout too.
If I had to hazard a guess, Cl / Cd (lift over drag or in F1 terms df / d) is the one area the RB20 excels in. Think most teams can easily match them on load but that’s where we are losing out big time on the RB