As others have said - you'll find this is more of a airplane/rental car/hotel/restaurant crowd, but for just about anything you'll find someone here who does it. There should be plenty of backpacking sites that have more people who can be helpful (maybe even run by the same company - IB also runs bikeforums.net, a bike site that I frequented for many years)
It depends a lot on your backpacking mode. I've been trending toward ultralight since I started bikepacking - you start with a ~20+lb penalty (the bike) before you even start putting on bags. My packing alternates between SoCal, where no fire at all is allowed a lot the time, and little water is available, and the Pacific Northwest where you can have fires and water falls from the sky. For trips of just a few days I tend to bring stuff that can be eaten cold, and don't eat much that would look like a meal at home. An added factor is that no flames at all (no stoves, not even cigarettes outside your car) are allowed in the Angeles National Forest most of the time.
Breakfast can be overnight oats - soak the oatmeal overnight with a cover and throw in some trail mix in the morning and it's a decent lightweight meal that's cheaper than a dehydrated meal.
Lunch is snacky things, really more just eating more of what I'd be snacking on during breaks. Trail mix of various sorts (Trader Joe's has decent variety), Fig bars, peanut butter pretzel nuggets (like a tiny peanut butter sandwich). Trader Joe's dried mini bananas are like crack with super energy. Maybe something like peanut butter sandwiches on bagels or other firm bread for a "fancy" lunch.
Dinner might be a pre-made rice and bean burrito (made at home with fully cooked stuff), or even just tortillas with cheese and salsa, and maybe some different snacks as a side, and a bit of chocolate for dessert. Lots of cheeses will keep for days without refrigeration. You can get little packets (like ketchup packets) of things like tapatio and tabasco to spice things up. I used to liberate a few when I ate at Wahoo at LAX when it was still open pre-covid. You can also precook pasta with olive oil and put in some lightly sautéed or raw vegetables plus some kind of protein and carry it a day or two without refrigeration, depending on where you are. If I have a stove and water then some kind of noodles (regular pasta or ramen) with a simple sauce that can be mixed dry in a ziplock and then added after cooking. You can make a nice spicy peanut sauce with powdered peanut butter, ginger, and dried hot peppers.
There are various cookbooks, too.
has lots of stuff that's intended for cyclists to carry in a pocket, but can work just as well for backpacking. It includes various desserty things, as well as things like rice balls wrapped in nori that can be a nice savory snack or meal.