Way too many people thinking that Excalibur's wielding was based on "worth", like it was mjolnir.
It was defined as "the act could not be performed except by 'the true king,' meaning the divinely appointed king or true heir of Uther Pendragon"
Arthur was able to wield Excalibur literally because the sword belonged to his dad. There is no separate "worth" notion here, its the divine right of kingly inheritance.
I guess there is some wiggle room that God could have appointed someone else as the "divinely-appointed king", but the whole point was that the way God appointed kings was by bloodright. Worthy souls were placed into the bodies of royal newborns.
So, who can wield Excalibur? The Pendragon bloodline. Done and done.
(also, "wield" just means who can control its power. its not unliftable like mjolnir, anyone can hold excalibur but it wont perform at its magical level for non-Pendragons, it'll just be a mundane sword)