What do you mean by "proc correctly"?
His A1 has a percentage chance to activate, after which accuracy vs resistance will determine whether the debuff extension applies.
Personally, I have him on my CB team - he's absolutely MVP. I've got him geared in survival stats:
44K HP
2666 ATK
3398 DEF
188 SPD
26% CR
165% CD
198 RES
231 ACC
He's far from optimally geared, but he gets the job done. When I have the time/resources, I'll be trying to get that CR up to closer to 50-60%, and the speed up above 190 for UNM.
My Vizier is fully booked, has 88% CR and 331 acc.
Idk why he only procs his a1 about 60% of the time.
Assuming you're talking about vs void affin, fully booked you get a 50% chance on his A1. That means you'll, on average, get at least one proc roughly 88% of the time.
My expectation is simple confirmation bias. I have him only booked for the 10% on his A1, so mine procs 45% of the time, and I can reliably count on at least one proc per turn. Nonetheless, I do always try to make sure I never let it drop below two turns on the debuffs.
Skullcrusher or some other CA champ goes a long way towards making sure the debuffs stick.
im lucky though im running a slow counter team with skullcrusher which vizier gets extra a1 attempts quite alot
vizier turned my 4 key if i was lucky ultra cb team team into a easy 3 keys ultra 1 key nm cb team, obv team synergy was the key
altan def aura & dec attack, rhazin a2 dec def & weaken, frozen banshee poison sensitivity & poisons, vizier extension debuffs and skull crusher counter
im hitting between 29 to 35 mil per key depending on rng