this is similar to an exercise David Foster Wallace would do — take a longish piece of prose, read it once, then try to replicate it exactly without looking.
Assuming it’s long enough that you can’t hold it in working memory, you’ll end up with something that shows you the difference between your own instinctive writing style and whatever you are copying.
Side note, but this is quite similar to how Raymond Chandler taught himself to write (around age 40 IIRC). He'd take a short story he liked, make a detailed outline of the plot, then write a story from the outline and compare it to the original.
Assuming it’s long enough that you can’t hold it in working memory, you’ll end up with something that shows you the difference between your own instinctive writing style and whatever you are copying.