That makes sense, I mean the juubi didn't even put up a fight when madara became its jin. I cant rep you sadly. :c
Even after Madara adsorbed her(Shinju), she not starting any mental/spiritual attack on Madara but wait for BZ do the outer job.
And from that, I'm able to speculate, that is how BZ able to penetrated Madara body easily.
look at below scan
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On the scan, we saw Obito's spiritual body/Will got teared apart by Juubi/Kaguya from inside, that's mean she tried to consume him. But failed in the end.
But from that events, I can say that's how Kaguya weaken up Madara body from inside and give an easy way for BZ to stabbing him. Sure there are no sub-dimension fight for Madara unlike Obito, but Kaguya manage to alter Madara body and lower the durability of his body.