Self-composed mate in 4, not difficult

he's not path cause of the pawn, move rook and bring it to the 8's lane

I tried a last one with the King being more active, alas still 9 pieces. Position mirrored, I had to see something slight different. :)

lichess.org/editor/k7/p7/8/K3B2P/5p2/8/3PR3/6N1 w - - 0 0

Yet another one, starting with the Rook "hanging".

lichess.org/editor/k7/p2N4/8/1K2P2P/1P3p2/2P1R3/8/6N1 w - - 0 1"]

I Like #9 better. Promotion to queen is too brutal to be esthetic.

Yeah, probably. But #9 taking on g3 has several duals. Here are no duals in both lines as far as I can see. Moreover, the queening line is the bonus side-line.

Next try :D

lichess.org/editor/k7/P7/1K6/P7/6p1/6N1/RP6/8 w - - 0 1

This is by far the more elegant. Now condensed to 8 men. The manoeuvre is less obvious without knowing the preceding tries. Maybe replace pawn a7 by Ba7. The doubled a-pawns and the b-pawn on its starting square implicate some c-pawn had to capture twice to get on the a-file. A bishop on a7 also makes possible other ideas starting with Bb8, which do not lead to #4, i.e. it makes the knight move less Obvious.