I would recommend you to wait two weeks for the significantly upgraded definitive version that you will get for free. Check YouTube for builds. Be aware of the split attack/defense system which separates physics and magic, decide whether you want a pure physical, pure magical or a split damage team. Everything is viable, the "classes" (more like roles) varied, and the combat system is fun. You want damage to penetrate shields, then crowd control (cc) to render the enemies harmless.
I think necromancer hybrid played as an elf (or elf undead or someone with the early game magic item mask of the shapeshifter), can combine the elven racial trait flesh sacrifice and the talent elemental affinity to very good effect. And also the living armor talent to replenish magic armor automatically through damage. Max warfare (best phys. damage per point invest) and a decent amount of necromancy. Intelligence should be main attribute (max eventually). Use wand and shield. Grab bouncing shield, deflective barrier, mosquito swarm, infect, raining blood (hydro/necro), blood sucker, corpse explosion (pyro/necro), death wish+living on the edge and more. Always make room for a transportation skill as much of the combat is about positioning.
Wiki:
https://divinityoriginalsin2.wiki.fextralife.com/Divinity+Original+Sin+2+Wiki
