The 4-2-3-1: why almost every big team still uses it
Not because it is the prettiest shape, but because it is the most balanced one.
Open five Champions League matches at random and three will feature a 4-2-3-1. It is not new, yet it survives every trend.
The reason is not beauty but balance: four at the back, two protecting the middle, four within reach of the attack.
The basic structure
Four defenders give natural width, the double pivot protects the centre and starts build-up.
Why the double pivot matters
One presses while the other covers, so the team does not have to choose between pressing and defending.
Weaknesses rarely discussed
It depends heavily on the number ten, and both full-backs advancing leaves the centre-backs exposed.
Modern variants
Many sides now shift into a 3-2-5 in possession while keeping the same base.
Conclusion
Formations never win alone; understanding the phases does.