To be fair, Pokemon Masters primarily follow the game's lore in a very composite sense(for example, Red, Blue AND Green are all "Battle Legends" to some degree and followed somewhat similar beats to Gen 1(Red for most of it, Blue as the obvious rival and Green apparently went through some of it) so it does make sense that they would treat Ash as his own character completely divorced from Red in this Continuity.
And yeah, I actually like they are actually trying to give Cynthia something to do by trying to be the first person to truly defeat Red. She may be a Champion but Red is a God lol.