hi, i have countered this formation many times before, my favourite counter for 4-3n-1-2 is:
3n-1-3w-1-2 - normal mentality, mixed passing, mixed focus, own half, zonal, hard tackling, yes counter, no offside. red arrows on AMC and STs

other suggestions are:
3n-1-3n-2w-1 - attacking, down both flanks, mixed, zonal, own half, no counter, yes offside. red arrows on AML/R and STs
3n-1-4-2 - attacking, down both flanks, mixed/long, whole pitch, zonal, yes offside, no counter. red arrows on ML/MR and STs

good luck mate.