I will probably whip up, like, skill/burst/talent specifics later to go full on nerd, but:

Weapon type: Catalyst
> Scientifically minded, she is going to be very invested in studying magic and alchemy and figuring out how this world's rules work as well as how to use these new tools available to her
> She'll have her guns from home (and will want to craft new ammo types for them), and is definitely more of a ranged weapons type than anything melee, but wouldn't have the patience for learning how to use a bow

Playstyle:
> Shield generation via skill (a la Diona)
> Damage scaling with lower HP (a la Hu Tao), though Zetta is not going to seek this out bc pain sucks
> Whatever her burst would be, it'd be explosive...
> Boosting ally crit rate ("That looks like the weak point, get it" - Especially versus things like Ruin Guards, etc, anything mechanical)
> Affecting enemy movement (think electricity-stunning style)