Sugar

There is no particular limit on inherent sugar -- the places that have come up with one just based it on a guess as to how much sugar people would be eating who ate the recommended amounts of fruits and veg and dairy (most don't) plus the max added sugar currently recommended. MFP's 15% is similarly just based on increasing the 10% max for added sugar (which is really about nutritional balance and calories, not sugar itself being bad) to account for some inherent sugar. None of these work well for someone who eats a lot of foods with inherent sugar, like say many WFPB people, or just people who prefer fruits and veg to starches.

That said, I think it makes sense to focus on sugar not taking space that you need for other things important in a healthy diet. So, make sure you have the right calories, enough protein, enough healthy fats, enough vegetables (just lots of fruit isn't the same), and are feeling satiated. If so, is the sugar mostly from whole food sources or otherwise nutrient dense ones (other than maybe on a rare day)? No need to focus on specific numbers if all this is the case.

Switching sugar for fiber also works for lots of people, in the theory that if you are within carbs (as sugar is a carb) and have adequate fiber, then you are mostly getting your carbs (including sugar) from more nutrient dense sources.

Without going into massive technical detail. Circa 50g sugar as a max is ballpark. This would depend on factors such as height weight age and activity. Dependant on goal calories intake would be the most factor then macros