But you don't own the art. You own the receipt for the purchase of a hash of the specific digital format the art is stored in.
Note that there are definitely currently ways for digital artists to make expensive art, and that's in the form of commissions. If you really want to support an artist, find one you really like, and pay for a commission from them. You may also be able to pay more for forms of copyright (like reproduction).
NFTs are the worst possible way for artists to make money from digital art.
Many artists do not want to do commissions. In fact, you could argue that people who want commissions are very selfish. Not only do they want to force artists to work on their thing, often driven by vanity, they even want to own the copyrights to the work!
NFT buyers are clearly more respectful of an artists craft: They buy the work the artist really wanted to create, and they respect the fact that they cannot be the owner of the work in a moral sense.
Not so; many (but not the majority) NFTs (like Board Ape Yacht Club) come with very liberal licenses that afford the owner of the NFT the ability to do a lot with them.
Note that there are definitely currently ways for digital artists to make expensive art, and that's in the form of commissions. If you really want to support an artist, find one you really like, and pay for a commission from them. You may also be able to pay more for forms of copyright (like reproduction).
NFTs are the worst possible way for artists to make money from digital art.