2. A team with a back-three of Rudiger, Alaba and Militao
This is a formation that can be deployed by Carlo Ancelotti if he still sees David Alaba as an even better centre-back than a left-back. A back three with Alaba, Rudiger and Militao can be rock solid, make Real Madrid more press-resistant in the build-up, and help the team cover up a lot of gaps in defence with a wide backline. After all, Rudiger’s best form was witnessed in a back-three at Chelsea. (This doesn’t mean that he can’t play in a four-man defence)
And coming to the wing-backs, two options for the RWB position will be Dani Carvajal and Fede Valverde. Playing as a right-back might ask too much from Fede Valverde in defence, but as a wing-back, the lightning-quick Uruguayan will have a little more freedom. Even while playing as a midfielder, he has pretty much been a wide player, and I see him succeeding there. Even Carvajal might be better in a role with lesser defensive responsibility.
As for the left wing-back position, the current left-back Ferland Mendy can be an option. But I think he’s too defensive to be a perfect fit for the role. An attacking left-back like Miguel Gutierrez can be a great choice, but his fitness is always a doubt. If we think out of the box, we can also imagine Vini Jr as an inverted LWB in a 3-5-2 that has Benzema and Mbappe up front, with “imagine” being the keyword here.
But I can’t see this formation being used by Ancelotti next season. An attack-minded manager like him might not prefer a three-man backline. The usage of a three-man defence doesn’t necessarily imply a defensive approach, but proper execution is needed to set up a winning team like Tuchel’s Chelsea and Conte’s teams.