Too much sugar is unhealthy.... too much of anything is unhealthy, even water

Though, natural sugars in fruit are inherently much healthier than processed sugar.

It’s natural sugar though, not processed. But you still wouldn’t want to eat too many

I don't think sugar in itself is unhealthy. Just the way we eat. I am type 1 diabetic. I often have hypos. My blood glucose goes too low. And I need fast carbs. That means lucozade. Very unhealthy as a habit, but needed at the time.
In my country we can't buy mango but it's in orange and mango squash which I love.
In short, the important thing is to have a balanced diet. If we avoided everything they tell us is unhealthy, we wouldn't have anything left to eat!

Every fruit has sugar that if consumed on a high level could be unhealthy.

refined sugars are the unhealthy ones. But if you’re diabetic or something, mangoes are still very high in sugar content.

I don't care , I like mango.

Every fruit has sugar. Sugar is only unhealthy if consumed in high amounts and especially when the sugar is refinded and eaten devoid of nutrients and or fiber which slows absorbtion.
So in other words your question dosen't make any sense from a medical point of view.
All sugar is sugar. Eating sugar in fruit is healthier than eating a bowl of cereal or a slice of bread because fruit has fiber and nutrients.

No. Only if you eat an excessive amount.