Well, I'll be damned. My secrets have been revealed. I feel flattered that you made a case study of my art style, you match it quite well, I guess I could give a little insight on what I usually use for my stuff.
As for my lineart I use colodraw's brush pack collection, specifically a pen named "Succubus Line Art", which gives a texture similar to a real ink pen, with a few white outlines on the sides, this is an inking exclusive brush as if you try any other color the outline will be more noticeable and kinda ruins it.
For my shading process, yep, I use this oil painting type of brush which a friend gave me one day and have never stopped using it since, I think it looks good, but at times I also use this Watercolor one, which, eh, I haven't used it aside for like one or two pieces. (I used it for texture in my Ragatha x Silent Hill 2 piece)
For that halftone texture, I use a CSP material I found the other day by this korean user just named "lllIIll", I put it in my canvas, adjust the size so it is noticeable and I either use soft light or Overlay at 30-40% opacity.
I'll leave links to some of the resources I use, I know it is no fun when a magician reveals his secrets, but I feel it never hurts to give people resources to try out new stuff like I do, cuz yeah, like you said, I tend to experiment a lot as I like to follow many artists and sometimes they leave their brushes in their discords or behind a paywall, I don't mind paying for them if it means I gain some form of knowledge, the same goes for any speedpaint. But yeah.
Nice piece, Shok and nice study, glad I was the subject this time.