trying out using concepts as a digital sketchbook and so far im really liking it a lot. really big feature for me is the infinite canvas bit so i can just keep adding more stuff to sketch pages i dedicate to whatever. i'm only using the free version and i'm pretty happy with what it does manage to offer (only caveat of the free version being you can't select/move parts of your drawing without being on the pro plan, but if you do just treat it like a sketchbook and draw over your other stuff or just move to a different area it doesnt really matter too much) and it does have some single purchase stuff for extra brushes/tools so you don't have to do the whole fucking subscription thing to get the "maximum features" thing that it feels like every other art program does.
ive tried other digital sketchbooks apps before and idk there's just something that feels really good to me about the infinite canvas especially so i can just keep going and going, rather than in some other ones where you gotta keep making pages or separate docs for each page within a grouping or something. maybe this'll interest you if you've had a similar experience