I’ve read that potatoes have high vitamin c content but I’d that lost during cooking specifically frying
While cooking some foods do change their structure and can change how easily or difficult our bodies can absorb nutrients from the food - very rarely will cooking erase a whole micronutrition/vitamin from a food.
In potato’s case? The reason frying potatoes (I’m picturing things like french fries here) are not the go-to version of potato is because of the fat absorbed into the potato when cooking. Not because it removes the micronutrients.