Buy VTI by Dec 30, 2027.

im sitting on a ton of cash right now and i want to put a chunk in. im thinking of throwing another 15k into an etf. i was mostly thinking vti, because im very worried of the ai bubble to pop, would this be smart? my financial planner said hes very bullish for 2026, im wondering if i should do this instead of QQQ. anyone sharing thoughts would help