Watch this guys video of King Arthur.
There WAS no King Arthur. Anything close would have either been Irish or Roman, but, there wasn’t one man.
Also see my #5 above. :^)
British figures about whom the most books have been written probably (not sure of the order) are Shakespeare, King Arthur, and Robin Hood. :^)
I read this one years ago, it’s still in print, but I like cheap.
https://www.thriftbooks.com/w/king-arthur-the-true-story_graham-phillips_martin-keatman/422768/