I ride in north Florida where it's hot and humid most of the year. Flavor fatigue is a real concern so I use electrolyte capsules (Hammer Nutrition and another brand called Salt Lick both work great). In the hotter season I take 1 every 1-2 hours. In the cool season I might take 1 every 3 hours on a brevet.
For nutrition I've been using Hammer's Perpetuum powder which is available in bulk and is naturally derived.
On most long rides I have a bottle of plain water, and a 1-2 bottles of Perpetuum, electrolyte tablets, and a combination of real whole foods, gas station/dollar general store junk, and always a few gels or blocks for emergency use. Also if the ride has lots of climbing (obviously not in FL) or bumpy gravel sectors I like to bring more gels cause they are quick and easy to use and digest in rougher conditions.
Real food for me includes: dried dates and figs, bananas, peanut butter and jelly or banana sandwich (my neighbor brings PB and banana dogs, yep PB and banana on a hot dog bun, or wrap it in a tortilla). I like PB and guava paste sandwiches cause the guava paste is thick and doesn't squish out all over everything like jelly. In north FL we can only carry chocolate on winter rides, and even then only if the hi is 70F, otherwise it melts. I also like to roast smaller sweet potatoes whole with the skin on and bring those sometimes. It's tasty and easy to eat and basically an energy gel that grows under ground. I make biscuits often and have been known to take honey biscuits on rides. Homeade waffle sandwiches are nice and portable too. If you don't already like to cook this might all sound ridiculous but if you like cooking just figure out things you like and can be portable. Another local rando makes focaccia or deep dish pizza the night before and brings slices of that. I can't stand Subway and am pretty sure I only ever ate 1 subway sandwich in all my 1,000's of kms ridden. However, the Hunt Brothers gas station pizza is highly recommended. If there are Cuban diners or cafes in your area (some central FL and south FL brevets) check them out for pastries, coffee, arepas and pressed sandwiches (scrambled egg and cheese is my fav), tropical fruit smoothies (called batidos with milk or licuados without milk usually).
Gas station/dollar store junk I go for: poptarts, gummy bears, plain fritos, fig bars, biscuit if you're in north Florida or GA, coffee in a can, coke/dr. pepper, V8.
I pretty much only drink gatorade on the really long hot rides when I want something cold and the sugar and extra electrolytes can be refreshing. I know a rider who on multiple occasions I've seen carrying a half pint bottle of maple syrup in his jersey pocket like a flask. And now there are one or two brands (one by VT gravel cyclist Ted King) that are marketing maple syrup in individual serving packets as a natural energy gel.
A mix of complex and simple carbohydrates is important and bits of protein (nuts, yogurt, jerky) on the really long rides. For the most part I lay off lots of fried stuff, meat and dairy in the heat, but then again I'm used to eating that way. I'm not vegetarian, but I was for many years. I'll eat a burger after a ride for the protein, but in the heat lots of dairy and meat doesn't work for me during a ride. Have fun figuring it out and know that some of it is just a matter of pushing your body and conditioning your mind and gut to the longer distances and you'll figure it out. Also bring Tums (antacid tablets) just in case you overeat or get heartburn, and remember, sometimes you might just need an antacid or to hit the bathroom and you'll feel 1,000% better afterwards.
Happy eating, err I mean, riding.