@grandslam Your goal is sexiness. And you talk about diet, so I'm guessing you think you need to lose fat to be sexy. We'll talk about diet shortly.
If you have 3 hours a week for exercise, and that's it, I would structure a very dense workout, that uses a majority of compound movements, antagonist or agonist/peripheral supersets. Aiming to hit all major muscle groups with 6 hard sets per week (not including warm up), and ideally have about 20 minutes per session to do some vigorous intensity steady state (or HIIT) conditioning. Since your time is so limited, you will want to structure your workouts to use the highest stimulus exercises, regardless of the fatigue, because it's unlikely you'll be able to train enough to exceed your recovery ability. Of course just make sure to use good technique and don't just add weight all the time at the expense of range of motion and proper tempo.
If you're interested in learning how to design your own program check this out:
It can take some time to design the perfect arrangement of exercises, it depends on your equipment, your gym layout, your preferences, and how you fatigue throughout the session, but just remember the problem you're optimizing for is maximal stimulus in the shortest possible time.
So the exercise piece is an essential part of sexiness (looking more brawny than scrawny), but you will get a lot if not the most effect from losing fat.
If you have money, but don't have time, meal prep services might be the best way to get you on track to fat loss. But in order for the changes to stick, without tracking your food, you will likely need broad changes in your eating environment, food environment, eating patterns in general, and your behaviors around food.
Even if you did decide to track food, you likely need to make broad structural and behavioral changes in order for this to be a sustainable lifestyle. If you're not sure what I'm talking about, I can elaborate.