I'm afraid I don't know how to replicate that effect in Clip Studio. I did, however make a couple of new brushes (just for you!) and added them to my set: My Current Clip Studio Paint Brushes
The one you're looking for is called 'Oil Sponge'. It doesn't behave the same way as Sinix's brush, but it achieves a similar effect of cutting and blending. The Oil Sponge brush behaves differently based on the amount of pressure you use. With a very light touch it's a blending brush, but as you press harder the brush tightens up and becomes sharper while laying down more colour. So you press hard to get those sharp edges, then blend it out using barely any pressure at all. 'Oil Bristle' behaves in a similar manner but with more of a bristled look.
If you really want something that behaves more like the Dry Brush Sinix uses but can't afford Corel Painter, you might consider trying Corel Painter Essentials 5. It doesn't have the exact same brush (I checked), but it has brushes that behave in much the same way. I mostly mention it because it's on HumbleBundle for another four days, for around 9 dollars. There's also a free trial of it, so you can try the brushes it has for free.