Nothing wrong with your png screenshot but does the black background originally come from transparency ? That is, is the original, the desturated shape on transparency.
You might have to remove that black BG and I might do it like this.
Make the black and white images first. Black (1) is black layer in soft-light mode then a new-from-visible. White (2) is white layer in overlay mode, then new-from-visible.
Put those, new-from-visible, in a layer group (3) (I used copies just for the example) add a layer mask to separate. White layer mask, paint in black or fill a selection.
You might have to remove that black BG and I might do it like this.
Make the black and white images first. Black (1) is black layer in soft-light mode then a new-from-visible. White (2) is white layer in overlay mode, then new-from-visible.
Put those, new-from-visible, in a layer group (3) (I used copies just for the example) add a layer mask to separate. White layer mask, paint in black or fill a selection.