Troubles dealing with Brush

[Red_Force]

Hi all,

I am a veteran in Computer Arts. I have a good experience of Photoshop oc, but also Corel Painter (not suited for real work IMO), SAI, Illuststudio / Clip Studio Paint for the main ones. The later being my go to setup where I have all my settings adjusted.
Working on a Cintiq 27 QHD and an SP4.

I had my sight on Artrage since the first release. I appreciate the brush tech, which seems to do what Painted aimed at but with proficient coding skill (ie it works, performance wise) and a slick UI. When my 9 yo son was starting to get frustrated with other apps on his Surface 3 (Krita being a bug fest there...) I remembered ArtRage and when I found about the discount, I bought it. I am glad to say he's a much happier camper than he's ever been so far on the digital art front.

That being said I tried to give it a go on the cintiq and I am a bit puzzled by some "very much in your face" issues.

- brush sizes : some are way too small. Standard pro format for print will be something like A4, 600 dpi. Even Artrage offer A3 300 dpi. In those mode, aerographe could use up to 3000% (!) size to be useful. Also not tying Brush size to preset seems a bit crazy. Puzzled by the design decisions!
- no flat brush? That's the main "natural painting" brush. Usually you don't need art pen to be able to have your flat brush working fine (ie you make a large line, take a 90° angle without rotating to a fine line, then another one, still with barrel rotation untouched, to use the largest bit of the brush again, as seen here) but I've been unable to get that to work in Artrage, even /w my Wacom Art Pen that I read is supposed to be supported. I can see square brush but square brush aren't a thing IRL and they kind of defeat the point of what's good about flat brushes. Puzzled by the design decision!
- touch (let alone multi touch) support is terrible ATM. I have read a post where it's blamed on Wacom doing their own "multi touch" being annoying from an app dev standpoint (which I get) but the thing is, multi touch wacom gesture are disabled on my rig and yet it works like a charm every where else but on Artrage. I can use Clip Studio delighful pan, rotate, zoom, undo and redo without using my (not working BTW, this thing is crap) EK Remote or keyboard. Needless to say, no zoom, rotate and pan on touch is kind of a deal breaker here

Any thing here I got wrong as a user ? Or are those real flaws in Artrage ? I hope I am wrong. The brushes are of interest for sure.