I dont know about best formation, but i gave this a try out of sheer boredom / frustration at being unable to play in the horrible gameplay with "normal" formations.

I did the 5212, both wingbacks on "join the attack" but both CMs on stay back, both strikers on get in behind. Creates a nice big space for the CAM. Used Scream Bernard at LWB as he has 99 stamina, Semedo at RWB and Dembele at CAM.

2 games and it did feel nice and controlled. First game i won against a good player - the type i respect, he played a passing game, nice slowed down dribbling and used Modric, Rakitic and Suarez so anything but the Meta.

Next game, the polar opposite, Sweaty Meta with POTM Vardy up top, Zaha CAM and ASM RW. First half he didnt have a shot, but i only managed one goal because Prime Icon Joe Gomez was blocking everything and Lloris was saving what he didnt. Second half he turned on constant pressure though and my team melted, couldnt pass. He equalised from it but with the last kick supersub CAM Bruno Fernange Winner.

Im sure with even more suited players and different CT it could be even better (i just used balanced / balanced with pretty netural settings)