Starting formations are a meme. In Alonso's own words (translated):
- "Formations are starting points. Spots on a board. Back 3? Back 4? It doesn't matter. The principles and behaviours inside the structure are what matters. Teams don't spend the 90 (minutes) glued to a position. There's fluidity, practical things in and out of possession."
- "We don't talk much about the start formation - 3-2-4-1, 3-2-2-3. It's more about what we think might happen in the game. Positional play is important. For example, the more passes we give in their half the better position you end up in for counterpressing. If we start playing too vertical, too far and too quick to the other half, the players are spread out and the lines will be too far away from each other, so then it's impossible to press properly."
Alonso, Pep, Enrique, Inzaghi, Klopp, Conte and others have all talked about the importance of finding a way to attack with 5. Doesn't matter the starting formation. The goal is to have a 3-2-5 or 2-3-5 in possession to create overloads when you have the ball and an instant effective counterpress when you lose it.
I've never agreed with the narrative of us being more attacking/"United DNA" under Carrick than the last manager just because of the starting formation. Shaw's still playing as a LCB for all intents. We now attack with 4 under Carrick. (Sesko, Mbeumo, Cunha, Bruno). Dalot occassionally joins in, but rarely and it's not ideal. We're suddenly unable to press at all.
Under Amorim we had the 5 that top coaches aim for. Sesko up front. Amad and Dorgu wide. Cunha + Mbeumo in the half-spaces, which suited both of their games. We were more patient in the build-up like Alonso talks about in the second quote ("playing too vertical"), and these two things combined gave us an actual pressing structure for the first time in years.
Our biggest problem under the last manager usually came when Bruno joined in, we attacked/pressed with 6 and then got beat up on transition if our initial press was bypassed.