What type of visa should I apply for if I'm planning to conduct an art project in Thailand and share proceeds?

Your art must be very plane

That is incorrect feedback. You stated “the proceeds…..” That means you are doing your trade in exchange for money. It doesn’t matter if you give an away every penny, it’s still paid job requiring a work permit to be legal.

If you don’t accept money, then it is not a “job” and you can perform your trade and give it all away or keep it for yourself.

Working without a work permit may cause you to get banned for a time.

As best I can see across the net there is no evidence that you are anything other than a hobbyist. That maybe hobbyist with aspirations. But in either case you would be no different from thousands using tourist visas and legitimately so, meaning for and in Thailand. There is no way that you can access anything else here in Thailand. However Thailand is not particularly normal in a region where a tourist visa can cover work-related activity and/or where a business visa is simply readily available (meaning on demand, no backdrop of invtations, etc). You should be looking to say Malaysia, Vietnam, Cambodia if you want to find more "blurry", more flexible and more realistic visa regimes, at the least to cover business meetings. If we are to ignore my first comment about "hobbyist" it would stilll be the case that all you have described is business meetings. At an aesthetic level those countries may sound less appealing than Thailand but that is likely only through having accepted greater commercialisation in Thailand. Hill tribes are the perfect example to consider.

The first thing you need to do is look at the reserved occupation list, many "artistic" occupations are covered. If what you do is on the list your done. If it's not your next thing to look at is if you can get a work permit and visa. Failing that you can only do it illegally