Zwey does GREAT in PVE if you know how to actually use it. It's a weapon of incredible timing and distance if used exclusively two-handed. Its best use is to preemptively stagger enemies who are trying to hit you - as soon as they come close, you start swinging, by the time their weapon is raised you should be driving yours through their chest. It's also crucial to understand your reach, as you can do a LOT better trying to hit from further out and using the massive weapon for its real strengths - the high single-strike damage, and the long reach.
The moveset has served me greatly, all 2h.
The strong attack will outright demolish enemies, and if it doesn't, it leaves them laying on their stomach. Even if it doesn't hit it can stagger nearby enemies!
The weak attack has good enough speed and damage.
The roll-stab is pretty quick, and works extremely well when you roll past an enemy and do a 180 turn to stab them in the back (this can utilize the Hornet Ring's 'counterattack' buff).
The jump back (press dodge while NOT moving in any direction) followed by an attack does a jumping strike that can exploit a lot of enemies in their 'missed attack' frames, particularly silver knights and that bandit from the forest.
As an exclusive 2h weapon, it's one to use for fast combat, curiously enough. It works rather well with fast roll helping to get into position and gain enough clearance/timing to get an attack off, so you have to know your position and timing. When paired with a (great)shield it works for tank combat, encouraging you to deflect an attack and use the 'weapon bounced off' animation to spin up your own attack.