It was only a few months back that I found out that Vangelis couldn't read or write music notation. He would just improv play and record on a tape, recording additional parts and mixing as needed. If he needed to have other musicians involved, then he would hire someone to listen back and write down the notation.
Considering he recorded something like 35 albums, he was doing something right.
Vangelis is a bit funny and odd! Have a listen of Jon Anderson's (formerly of Yes) account of meeting and collaborating with Vangelis.
https://www.youtube.com/watch?v=ItV5h3Arl5M
You will love this video:
https://www.youtube.com/watch?v=2hA0z4GQjtA
You might be surprised at how many famous professional musicians don't read music notation. Outside of the classical world, session work, and jazz fake-books, it's far from de rigueur.
This is true. I read an interview with Hans Zimmer who has scored dozens of Hollywood films (including Blade Runner 2049) and when he first arrived in London in the 1980s he couldn’t read music. Not sure about now.
ETA: he did eventually learn how to read music:
“I learnt to read music after I bought the Roland MC8 Microcomposer, because it then became essential for me. … I learnt music by ear and have picked up most of my technical knowledge through the sessions and gigs.”
https://www.muzines.co.uk/articles/ronnys-electro-music-caba...
Dave Grohl is another one that comes to mind.
Also Kurt Cobain, as noted by Rick Beato:
"It doesn't matter if people know what they are doing, if they can just do it intuitively"
https://www.youtube.com/watch?v=l1ZnWc-sFd0