I want to acknowledge that this question is generally well-intended, but also want to point out that artists are working just like anyone else. If you want good artwork, you should expect to compensate the artist for their time and expertise. I’m not an artist, but IMO paying someone on Fiverr values art more than looking for a free option. I think that’s probably your best bet for the criteria you have. Alternatively you might try to commission someone you find online. Hope you find what you’re looking for!