Potatoes are vegetables? Rutabaga? Pumpking? Carrot? Turnip? They also punch high, and are consumed a lot by people that believes just "eating more veggies" would solve all their problems. And lets not talk about some fruits.

Wholegrain won't do magic here. Glycemic index of wholegrain flours and wholegrain products (bread, cookies...), even sugar free, can be higher than foods made with regular grain. E.g. glycemic index of butter cookies is 60-70 (https://glycemic-index.net/cookies-pastries/ https://glycemic-index-database.com/foods/butter-cookies-flo...), for a wholegrain baguette is 75 (https://glycemic-index.net/baguette-whole-grain/).