You need to break concentration, I rather like that mechanic. The best spell I `found` in this game bar none, is Magic Missile.
Enemy casters need to save for concentration on *every* missile hit. It's also the only spell that *always* hits and so far nothing I've seen so far [early act 3] is immune to it. It's even good against doors.
And this is why they also have Shield as a reaction to make cool mini mage duels.
Finesse like this doesn't exist in BG3 unfortunately. It's just drink Haste -> Fireball Fireball Fireball durrrr. Or drink Haste dip candle-> whack whack whack action surge whack whack everything dead durrrr.
