Fat/Carbs/Protein

Depends what you are wanting to achieve.

To lose weight, it is simply calories in / calories out - no matter what the macro make up is.

If you want to make sure you are not losing muscle mass in that weight loss, you need to get adequate protein in your diet. You also need adequate fats and carbs to keep your body absorbing nutrients, regulating blood sugar and hormones, digesting and a bunch of other things.

Personally I aim to reach my fibre and protein targets each day, because meeting these helps me to feel satisfied and makes the journey easier. You say you 'probably' eat too many carbs....if your carbs are coming from fruits and cereals then 'probably too much' might be the weight loss industry talking. You would need to keep a closer eye on your macros if you were wanting o achieve something specific - like building muscle mass.

"Now that...is the right question!"

Truth is, there isnt really a simple one solution. If your goal is to lose weight, then you eat at the percentages that help you achieve that goal. Some people eat 80% carbs, others 80% fat, while some manage 50% protein. It varies per person, but everyone is right if it helps the person achieve what they want to achieve. So, just pick a ratio and try it (not just from the three I listed)!