as far as i know a co-op is a model where all the employees share profits based on the work they do so it shouldnt be immoral. But also even if it was we live in a capitalist society we cant really help but participate in immoral systems to some extent if we want to survive. As long as your doing your best to be fair to people, and everything i dont see a problem with it. A lot of people will also just do stuff like that on their own tho so idk if you need a co-op for it. Like self publishing online is doable by yourself.
We live in a world where genocide is normalized if you try your best to not treat othere like shit your already doing better than most just chase your dream and dont be bad to people on purpose and if you make it big and have tons of money use it to help the people society has abandoned
you are by definition cooperating with others who accept the terms of the cooperative, usually involving equal share fo the profit as contributed to the project's costs (there's dozens of models and all are massively more equal than private-ownership businesses)