For me, here could be the match ups:

White beard vs black beard and allies

Kuzan vs Oden

There's a chance black beard will fight dirty, like having some white beard pirates betray white beard, or some other trick

This is an overkill.

Ok, the whitebeard pirates take the win low to mid diff but they were much weaker than the roger pirates. Whitebeard was carrying and even though they often clashed it was clear what the difference was when we had that flashback. The vice captains rayleigh and marco had a clash and rayleigh stopped him with a finger (Haki tho). So the power gap isn't insane but whitebeard pirates still win

Maybe it will change in the final saga of one piece, who knows black beard may has some crazy trick(ngl white beard solos)

Yea lowkey if the theory abt BB having three devil fruits and the last on being a zoan is right then he could become insanely strong

BB after stealing Marco’s devil fruit

@SEKIOP Marco was not WB's right hand at that time. He was an apprentice.

WB and Roger were on equal grounds. Oden was relative to either Rayleigh or Gaban, but he couldn't take on both at once, and that's the problem. Even though BB and Marco (WB Apprentices) could beat Shanks and Buggy (Roger Apprentices), Rayleigh/Gaban would still smash them all.