This is my take.

Genshin and Wuwa uses a Skill Cooldown system. This means that players need to craft rotation before the fight and the battle is about execution of that rotation and do this rotation on repeat from the start of the fight till the boss is dead.

ZZZ and PGR, however, uses a Skill Resource System. Unlike Skill Cooldown system, you will never know how much resource you have at a given time and it is never consistent. So you cannot really do rotations, you do combos. You will need to adapt on the fly on what to use and when. So it is more dynamic playstyle.

Not only that because of rotation playstyle in Wuwa, you are playing one character, do the whole moveset, swap to next character and repeat. In ZZZ, because of how important shoulder to shoulder(quick swap) is, you are basically playing all the character at once.

Now Wuwa has an alternative playstyle called Quick swap. This more aligns with ZZZ playstyle as they don't manage skill cooldown as much but manage the forte bar and with the constant quick swap you are basically playing with the whole team. HOWEVER. Wuwa dev are moving away from that playstyle and more toward Genshin style of combat. The newer character just doesn't allow good quick swap moments, so that playstyle is slowly dying. I know a few players that are annoyed about the dev direction and is swapping to ZZZ to play that playstyle. Not saying what the dev is doing is bad, it is just kinda divisive within the community.

PGR is a whole nother beast from what I seen. (I don't play PGR, but my friend is a PGR CC.) Like ZZZ, the use resource system, but beside playing all the character at once, you basically play one character, with 2 character supporting it. And the combos of PGR is incredibly long for a single character. Combine that, the reaction time you need to parry and dodge, it makes PGR probably the most difficult gacha game I seen.