Has anyone successfully managed to monetise their Midjourney output yet?

I’m looking to make shirts with designs/patterns focused on animals using AI (Midjourney), like dogs, cats, owls, birds, etc. Do you think having such a broad niche (since there are many types of animals, both aquatic and terrestrial) is a good idea, or is it something difficult? Is it better to choose a sub-niche, such as ‘birds’, or can I go for a broader niche?