I haven't messed with Priest much besides using Xoti in my playthroughs, but Paladin and Chanter seem like good fits for a frontline Priest multiclass. With either multiclass, you double down on great supportive abilities and open up room in your party for more squishy damage dealers.
A more aggressive ranged priest might look like Priest of Berath/Helwalker monk. Use Enduring Dance for accuracy, and Helwalker bonuses to buff up Rot Skulls and Storm of Holy Fire. It would come together a little late, though, and you'd have to be careful not to take buffs from both classes that overwrite each other.
Generally, I feel like Priest is a weaker class in PoEII because many of the classes provide better buffs then the tier 1 buffs that Priests can hand out, and fights don't usually last long enough to make countering an affliction with an inspiration worthwhile.