Calories in, calories out.
Yes, you need a deficit for fat loss.
I would, however, if I were feeling particularly bold, advise that people do not opt for an extreme deficit, unless this is recommended by a professional who actually knows what they're doing. Even then, they would probably need strong guidance, I expect.
6'2", ~100kg (~220lbs). 40yo, training (with a few breaks) since my late 30s.
Squat 160kg (352.7lbs), Bench 112.5kg (248lbs), Deadlift 220kg (485lbs), Strict Press 75kg (165.3lbs)
My training log