If you struggle with it, if you are always wrestling with something not quite right, if it makes you nervous to share it, you are on the right track for sure!
I'm just saying, a guy like Van Gogh comes around just a few times a century, he is not somebody you can simply encode into a lot of different matrices, it takes a certain human life to make art like him, or even more simply, to simply see the world like him. Its not just about the way the sunflowers look, its about the choice in the first place to paint them, and making that choice in the particular context he was in, at the particular time in history he did. Its important that it was this painting that was painted after all the other paintings that had come before, both in particular for Van Gogh and for the world. And you can't ever recreate it, because its already done, and you can never step in the same river twice.
In general, and no offense to you in particular, but you will be forgotten as an artist. If this wasn't a certainty before, it is one now with all art generation and such. But don't take that as a bad thing, it is more than anything liberating. Try to remove all expectation and ego from what you are trying to make, and that will bring you closer to Van Gogh's work than any particular technique he used--your artwork should be completely personal, entirely internal, right up to the point that someone else see's it for the first time. It should only be judged on a sui generis rubric, more like a dream than a product. Stop, in general, trying to prove yourself on the basis of the tools you use. You could use sticks-and-twine or a million-GPU-DALL-E thing, whatever, its all orthogonal to the effect the final product might have, and that effect itself is only influenced by your attitude, your sincerity, and your vulnerability, as it is applied to the work.
(That is my maybe my main issue with the AI art bots, do the artists who work with them even feel vulnerable about their work? Can artistic sincerity and enthusiasm exist in AI art? Do AI artists feel the literally metaphysical stakes of what they are doing like Van Gogh did? Or is it all so constantly folded back into the idea of AI art itself? Is it all just different campaign posters for the cause of legitimizing itself as "real" art? Maybe just some time needs to pass, but I hope artists can still get nervous in the future, can still struggle at all to bring something out. I worry that people using this technology are too worried about proving themselves, they are not opening themselves up the possibility of failure that all artists need. They are not in a silent enough room to be able to hear what there brain is actually saying, only trying to respond respond respond. It is usually the struggle the artist has with themselves that is transmuted into the work such that it makes us cry or feel profound joy or sadness or whatever, we still need that psychic energy in the world, it doesn't need to be solved.)
To be like Van Gogh, you need to make art as if you would die and go to literal hell if you didn't, or go there if you made the "wrong" art. If you feel something like that, you are on the right track, but you still have 0.001% chance of dealing with that illness as productively as Van Gogh did.
The next Van Gogh, or the next Francis Bacon, or Rothko, or Cezanne, or whoever, will probably not have the machine-capturable-"style" of any of those people, but she will share in the particular mental complex they had, the same spiritual curse which drives one to reach past a scientific or practical world, to tap into something pure, almost completely formal, that cannot simply be taught or transmitted, much less encoded.