You're experiencing, lack of endurance fitness. You need to build upto 4hr rides with steady pacing.
Dont eat sugary foods, they will give you a short boost then your body craves more.
Use plain slow release carbs, oats, nuts, fats, maybe a banana too Drink only water. After a few months of building endurance whilst teaching your body to use fats as the primary source of energy. You should be better able to go further with less fuel
That doesn't mean you dont eat in rides, just a little less and foods which dont crash you after a boost.
Most riders can around 90mins without fuel before glycogen stores start to become depleted. So fuel every 30mins with a little plain food.
Dont get me wrong, gels have a use, but later on big rides, when fatigue is creeping in and a kick to get you over the line is useful, but not at the start of big rides