What should I multi-class my character into?

My character is a half-orc warlock. Her whole thing is that she has none of the typical half orc traits (she’s smart, not strong) and she’s lawful-good. Her subclass is the great old one and her patron has turned out to secretly be an old one masquerading as a regular goddess but we don’t know why yet. My plans for her is to go down a darker path because of the more eldritch powers she gains (like necromancy spells) and to lose her lawful-good status as she witnesses the prophecies that her god keeps showing her come true (her mentor/adoptive dad die, her hometown burn, etc).

My dm plans to multi-class us all at an appropriate point in our characters story, but I’m having trouble figuring out what class would best fit with the path she’s going down. Originally I was going with artificer because of the whole knowledge thing but since she’s following a darker path idk anymore. Any suggestions?