Take for example Kurt Cobain (whatever you think of him and his music). He had major success in music, but his life was a disaster and not something I'd hope for a loved one.
I do agree that it seems like the best art is created by "tortured artists".
What is life for? There are fundamental questions here and I don't think the answers are obvious as you seem to think.
J. S. Bach had some hardships in his life, but he wasn't tortured.
J. R. R. Tolkien, similarly, was not tortured.
da Vinci's life doesn't seem to have been horrible either.
I think they stand as strong counterexamples to the idea that tortured artists make the best art.
Certainly it would have been a traumatic experience.
Definitely a relevant point. Thanks for mentioning it.