There is no "best formation out there" just ones that work for you and some will change to counter their opponent, like play wingers if the other team plays with no full backs or use DMC if opponent uses AMC.

Curious about your 3-1-3-1-3, is that narrow as in 3x DC 1x DMC 3x MC 1x AMC 3x ST?

If so that is an illegal formation and would be the reason you was losing constantly, I found this out the hard way myself.