[warent]

If you have the money for it, you should really consider hiring a contract artist to supplement your gaps.

A concept artist and a 3D modeling artist altogether will cost like $3000 for 1 fully complete character that fits your vision. For 2D probably a lot cheaper.

For me, $3000 is worth the months/yrs of saved time.

Of course if you are having fun learning the art side and don't care about the destination as much then ignore this and have fun with it! If you practice every day for a year you'll probably start getting close to what you invision.

EDIT: I'll also add that it's possible most of the aesthetic you're looking for can be achieved via shaders (for both 3D and 2D games). A lot of art looks very different in-game because of shaders doing all kinds of manipulations.

[Cthulhu_]

They could start with stick figures and placeholder graphics to communicate the idea, then level up; a great example of this iterative approach is Factorio, which redid some of its graphics and graphics pipelines over the years, starting off with basically MS Paint style graphics, then moving to a detailed 3D model transformed to 2D sprites pipeline.

Then there's the Kingdom of Loathing games that never moved on from shitty Paint drawings, lol.