The exophonic writer most people know is Jozef Teodor Konrad Nalecz Korzeniowski who became Joseph Conrad of The Heart of Darkness fame. Fewer know that Jack Kerouac, born to French-Canadian parents, spoke only French until the age of six, when he started school. I, like Kerouac, learned English only when I started school, but, unlike Conrad and Kerouac, I am not a master of English prose.
BookWitty recently had an article which mentioned both of these celebrated writers as well as some others: https://www.bookwitty.com/text/exophonic-authors-or-writing-in-a-language-not/59e4880f50cef71947f61293.
If you are interested in other exopohonic writers, consult the list at Wikipedia: https://en.wikipedia.org/wiki/List_of_exophonic_writers. You may be surprised at how many you have read.