In an average day, I eat plenty of carbs. Here’s an example list:
1-2 bananas; 2-3 servings of berries, melon, or other fruit; 2 pieces of gluten-free bread, 2-3 servings of potatoes or rice.
In addition to that, a couple of times a week I’ll end the day with some wine, or dessert, or both.
But that’s my list, not yours. Also, notice that there were refined, processed, or added sugar items except for the dessert.
I can eat that much sugar because I earn it. I burn it off by exercising, not just in my training sessions (although that’s the bulk of it), but also, by moving around all day long.
I add in at least one mile of walking daily and ‘extra’ work whenever possible. If I’m near a bar, I do a few pull-ups. If I’m working late at work, I’ll do some push-ups right on my office floor.
You can eat plenty of sugar and stay thin, if you earn it.
Your metabolism will be different than mine, yes, that’s true. Your style of exercise won’t be the same, and neither will the list of carbs that you like.
But your ‘plenty’ can be plenty for you if you’re moving around enough.