when I saw the first trailer for the show, I thought it was an AI joke. I literally have no desire to see one second of any of the Star Trek stuff anymore, or Star Wars. I used to love Star Trek in Star Wars when I was a kid. George Lucas wrote Star Wars back then, and Gene Roddenberry wrote the Star Trek episodes. Now, the shows are written by the denizens of the Cantina from the original Star Wars
He wrote a few of them ... the vast majority came from other writers, some of whom were at the time, or later became, recognized Science Fiction writers in their own right.
He wrote concepts and did a lot of re-writes of others. He tweaked their writings.
D.C. Fontana wrote most of them.