Just wanted to leave my two cents here. Using the misc blending mode ‘dissolve’ adds quick dithering to a brush. In a way, it’s almost like combining subtract mode + plain/rgba/lightness map/etc? The effect isn’t perfect but it’s a start.
The image above came from Can anyone emulate this CSP brush in Krita? - #7 by anon62843690 You can download the brush there.
(brush above) Lightness map blending mode + dissolve gives an interesting result.