Coffeelock.
10 sorcerer, 2 warlock
Eldritch blast (3 blasts), doubled with metamagic + hex + agonizing blast
6d10 + 30 + 6d6 a turn
Save your spell slots for protection and mobility. You have all the damage you need in your cantrip.
I've been thinking about multiclassing wild magic sorcerer/pact of the archfey warlock for roleplaying reasons, but I haven't even thought about how much damage she could actually deal (I'm new to multiclassing).
I thought that if one source for the wild magic can be being blessed by a powerful fey, it would make sense to contact this fey when you want to learn more about the origins of your powers. And I want to see the warlock-patron interaction.