I think Kb2 will be followed by Rd8 which will be dangerous for white.
In this position, Black is slightly worse. The only leverage for white here is the pressure on the black king and active Rooks.
He should play more active like Rd7 followed by grabbing either the B7 or G7 pawn. Then he can try pushing his passed pawn or try to bring his king into the game(a bit later).
On a side note, he can try exchanging his Pawns to secure a Draw, because it will be challenging for Black to win.