First thing you are going to say that Bayern used a 4-2-3-1 system and that's right but the way they played were near to 4-1-4-1 system where Javi Martínez, Bastian Schweinsteiger, and Thomas Müller dominated the midfield. Of course, Muller isn't a midfield player but his position in the field is between the midfield and the attack which helped Bayern to compress the opponent in the middle and to help Mario in the attack.
Bayern used an amazing attacking style playing with narrow field size and high defensive line to compress the opponent in the middle and to have the ball early then play their style by attacking from everywhere in the field as Arjen Robben, Franck Ribéry, Thomas Müller and Bastian Schweinsteiger were the main source of the threat. The key to that style was the AMR,L,C helping in defending and making it hard for the opponent.
My tactic style is so close to that system, using wingers in " support " duty in the middle helped me to attack and defend well.Also using CM in " attack duty " helped me to create that role of Muller and his position in the field is between the attack and the middle. Mario is a defensive forward for sure but I had players don't suit that role so I used the Deep Lying Forward in attack duty to approach that style of scoring goals and the one who holds the ball while his teammates go forward.I used attacking full back to support the midfield players, overlap, create chances for everyone, and scoring goals.
It helped me with Getafe to win Liga 123 and to be in the 6th position in La Liga and play in the Europe League next season. With Valencia, I took the team from 11th to 3rd position and qualified to Champions League. Next season, I achieved La Liga which helps me to move to PSG in Summer.
It will help you so much against big teams and will dominate against small teams. It is not a possession style of play, it is all about playing forward and squeeze small teams in their half with counter-attacking mentality against big teams.