Vinicius did drift in a lot to pull Araujo out of position, but I don't think Araujo could follow him any more than he did, as then he'd leave Busquets isolated on the flank against the Madrid LB. One of Busquets or Kessie should have been on Vinicius when he started to pull Araujo out of position. Kessie did it for sometime, but he's just really slow and Busquets...let's not talk about him.
Imo, Araujo's biggest strenght is 1 vs 1 defending, and his biggest weakness is exchanges of positions with his partners in defense. Also counts that we have no RB in the team basically, so these players are often having to play on multiple positions during a season, which of course it affects the stability of the team.
Most of the marking exchanges Araujo had with Kounde and Alonso were a disaster in the dynamics of the match. Usually it's not a problem, but vs elite Ballon d'Or level players like Vinicius and Benzema, it can be very costly when they are on.
For example, Kounde and Araujo couldn't decide on the spot who takes Benzema and who stands a bit closer to Vini at the 1st goal. Both rush out to Benzema and leave Vinicius all alone. That's a defensive mistake, since the position Vinicius has is insanely dangerous. You don't double rush for a wider player and leave an unmarked player all open centrally at 8 meters.
These mistakes can be costly vs elite players. It's not a huge blunder, and it happens (especially since the defender's main instinct is to rush out and block the player with the ball), but we did make many errors of defensive interpretation and Xavi will be looking to address that I think.
Ancelotti did surprise Xavi with how mobile he had Vinicius playing. Vinicius had much more freedom to exploit central areas of the pitch than as usual. And our synchronizations in coping with that extra overloading of zones was bad.
That's the way you can exploit Araujo's weaknesses, not by staying very wide and looking to force 1 vs 1s all the time. He will be hard to beat in that scenario I agree with you on that.