If we just take Ryuuma, everything about his portrayal points to him being the epitome of swordsmanship and just strength in general, he's up there with Joyboy.
Ryuuma won all his battles in one attack. We see Admiral level individuals roaming the world like fuji and gb, why wouldn't it be the same case 400 years ago, there would have been Admirals leading attacks on Wano, maybe even God Knights at that time, and they all failed because of one singular individual who defeated them all in one attack
Meaning Ryuuma was one shotting top tiers. Roger couldn't even one shot a pre-voyage Oden.
Even post voyage oden, who based on everything we know is at least put in the same league as the likes of roger and wb, similar to how scopper and ray might be, is clearly portrayed below the God of The Blade.
Odens daughter was willing to trade the only tangible memory of her father, his sword, for Ryuuma's Black blade, because what Oden accomplished is nowhere near what Ryuuma accomplished, whose blade is a national treasure.
Furthermore luffy/ Joyboy, was only ever compared to Ryuuma after defeating Kaido through a series of multiple plot armor events (like Kaido sitting down and talking to luffy instead of finishing off when G5 ran out), and saving an entire nation from a decades long Tyrannical Reign.
Which mind you, no one wanted any part of, Not Prime Whitebeard after hearing Oden was defeated (and not knowing it was done in an under-handed fashion ) which speaks volumes of how strong WB thought Oden was, to be hesitant to face Kaido after assuming he beat Oden fair and square in a 1v1.
Nor Red-Hair Shanks who befriended Oden and knew him personally, and voyaged with him.
With all that being said, one can very safely assume Ryuuma who has the title of "God" is an intentional decision made by Oda for a very intentional reason.
Now if we even assume Mihawk is a weaker version of Ryuuma, even that would be a compliment, because Mihawk would at least have a comparable feat of swordsmanship to the God of The Blade, and this would make him superior to any non-blade combatant, combat wise. Meaning blow for blow Mihawk is certainly superior to Shanks, WB, Roger etc, his is the current pinnacle of mastery when it comes to wielding a weapon.
Literally no one in the One Piece world, until confirmed otherwise can match Mihawk in combat capability, Shanks who was a genius who could copy Rogers Kamusari just by witnessing it, is still stated to be inferior to Mihawk in swordsmanship.
So yes, Black Blade combatant > a non black blade combatant (Assuming they made it of course)