5-3n-2 is a very powerful formation as it is strong in the defense and fairly strong down the middle. My ideas to counter this formation would be to try 4-3n-2w-1, 3n-3n-2w-2 and 3-2-2-2-1 butterfly. 3-2-2-2-1 butterfly has helped me against flat formations before.

orders:
4-3n-2w-1 - attacking, down both flanks, mixed, hard tackling, zonal, own half, no counter, yes offside trap considering your against a flat formation. red arrows on AML/R and ST.
3-2-2-2-1 butterfly - attacking, down both flanks, short passing, zonal, own half/whole pitch, hard tackling, no counter, no offside. red arrows on AML/R and ST.
3n-3n-2w-2 - attacking, down both flanks, mixed passing, zonal, own half, hard tackling, no counter, yes offside, red arrows on AML/R and STs

just some suggestions, good luck.