Choice of food can help a lot with hunger. Low-carb and keto are popular here and there’s a reason why. I’m not keto myself, but I do try to eat lower carb meals. Since you’re having a hard time going more than 3 hours, I would switch to 3 low carb meals a day with time-restricted eating (eat in 30-60 mins, no snacks), do that a few days/week, then remove breakfast, do that a few days, then try a fast.
Personally it’s so much harder for me to fast on weekends when im less busy whereas when im working during week im so busy it’s easier not to think about foods. Ur gonna have an adjustment period where your body learns to access its fat stores. You’re gonna be hungry - you just have to get through it. Personally I’d recommend eating at noon then again around 6 as it’s better not to eat too late. The book Fast Feast Repeat has a 28 day start & different ways to approach IF. I’d check it out 😁 Good luck!