On paper definitively and canonically Mihawk is the strongest Swordsman. Which puts him in a league above Roger, Shanks, and Rayleigh. These three are legendary swordsman characters within the story of One Piece.
I think characters like Roger, Shanks, Whitebeard, and Luffy transcend these titles and labels via their charisma, political power, and connections.
Whether these characters are stronger or not does not matter, rather whomever follows them does. Which Mihawk even stated himself, the most powerful man on the seas is the one with allies.
@Kuro Ashi @Peroroncino Im just saying Oda could twist a narrative to make Shanks seem stronger because of his collaborative strength of Yonko power and influence. There will never be an in canon definitive answer stated. Rather a bunch of miscellaneous notions here and there paint the logical picture.