That many character names, place names and themes in the Wheel of Time are based on Arthurian Legend is hardly a secret. Some of the parallels are quite subtle. I didn’t make the connection between Egwene al’Vere and Guinevere until I came across it on some WoT fan site or other. Tar Valon and Avalon is another one I confess I failed to spot first time.
Robert Jordan’s premise is that through the cyclical machinations of the Wheel of Time, historical events and people in our real world turn up in highly distorted form as legends in the Wheel of Time universe and vice versa. There are some examples of the former in Chapter 4 of The Eye of the World where Thom Merrilin rattles off a list of tales he knows including “Lenn, who flew to the moon” (John Glenn), “Mosk the Giant (Moscow) and his wars with Elsbet, Queen of All (Queen Elizabeth)”, “Materese the Healer, Mother of the Wondrous Ind (Mother Teresa)”.
Most of the legend creation we encounter goes in the opposite direction, where characters and events described in the WoT books are presented as the retrofitted backstory to account for the Arthurian and other legends we are familiar with.
In some cases we have two WoT “origins” for a single Arthurian character. For example Arthur himself has two WoT antecedents, Artur Paendrag Tanreall (Artur Hawkwing) and Rand al’Thor (al’Thor -> Arthur). Both are great rulers, albeit at different times, and (under Jordan’s construct) the names have fused over repeated retellings into a single Arthur figure.
Another example is Merlin. We can postulate Thom Merrilin as an obvious antecedent noting his past role as Court Bard. But he cannot channel (do magic) so how is he known to us as a great wizard? The answer is in the second component from which the name Merlin is derived, namely the Amyrlin Seat, referring to a wielder of great magic power. Jordan wants us to imagine that the names of Merrilin and the Amyrlin have become conjoined into a single character named Merlin who is both attendant at a royal court and wielder of magic.