Hey there,
sorry for the slow reply, I think a lot of these types of groups have been losing activity so we would definitely love to get more contributors.
That being said, I'd love to take a look at some art for you and offer critique if you want it. Otherwise, I'd advise you to just go for it and submit a request to join as a contributor! Maybe in your request, link a few images that you are most proud of and that best show your skills so that the process can be expedited.
Thank you for the interest!!