Need formation advise how to beat 4 1 2 2 1

[FC Dacia Terra]

I play against a 4 5 1 v (this formation) using:

4141, that's a dmc 4 flat midfield and 1 striker

Normal/ defensive, both flanks, mixed passing length, counterattack on, but off can be fine too.
Low, normal/hard, zonal, no offside trap.

LeManiaque, how do I play against someone, a friend, from the association... We make tactics togheter, all and this season we play against each other in the league and the cup too. In the cup he won the first leg 3-2(0-2), and tomorrow we play the second leg. The issue is that he is always changing his tactics... He changes like 3-4 formations in one game. He plays 41221,4141,4231...what should I play against him?...