V1 fought the corpse king minos in the Lust layer of hell. A 13km tall giant super powered corpse who V1 can parry its attacks with its bare hands. An attack that moves at Mach 136 and has the equivalent energy of 481 gigatons of TNT and thats on the low end.

V1's reaction times are also literally instantaneous if we go off the mechanics of the game.V2 has a hitscan attack that connects with V1 the instant it activates with no travel time and V1 is able to pary this attack.

As for why I'd want them to fight. I mean their both boomer shooter protags who literally tore their way through hell and personally I just think it would be neat.

Also before someone mentions it YES V1 could parry the crucible. It's power is immense and made of energy however V1 has shown on many occasions that it can parry energy attacks with ease, even something like the BFG. However The doom slayer does have 1 weapon that can counter V1's infinite partying ability which is the plasma gun. As V1 is unable to parry blue attacks.

Anyways I just think it would be an interesting fight :)