Does anyone have any tips on how to eat more calories

I will probably get yelled at for less healthy habits but the truth is that health starts from an appropriate number of calories.

You can then add or subtract more or less healthy stuff; but if you don't get the Caloric balance right as the base of your pyramid then things will not work out

Most people who are trying to lose weight end up trying to moderate or remove from their daily lives things like potato chips, Cheetos, breakfast muffins, croissants, turnovers, donuts, desserts, cakes, cookies, crackers, high calorie snacks, ice creams, high calorie sauces, dressings, dips, cheese with it without wine, whipped cream, cream, cream and sugar combinations, chocolate bars, pasta or noodles, french fries, deep fried appetizers, pies both savory and sweet, burgers, pizzas, full sugar pop, takeout food such as curries with naan, garlic bread....

Why are they trying to moderate them when trying to maintain or lose weight?

Because ultra tasty ultra processed foods are not the greatest Caloric bargain and are often hard to moderate because they're tasty!

With a 600 Cal total breakfast and lunch combo I'm willing to bet you haven't been hitting your neighborhood fast food joints, restaurants, or bakeries... or even the "appropriate" aisles in the grocery store!

Doing 2700 Cal a carrot at a time will be a hard slog.... and that's coming from someone who will eat a 750g bag of them in a day like yesterday. Plus another 1100Cal or so from an easy couple of 100g Cadbury chocolate bars... unless I really try not to! 🤯

What are you goals and what is your height and weight.