If you considering purcahsing and travel time to the store, recipe research, cooking the recipe, eating the food, cleaning the kitchen and the dishes, it adds up to a lot of time each day/week. Maybe not as much as sleeping but as a single adult living alone i probably spend at least 2-3 hours worth a day on the above tasks.
That's if you're doing it inefficiently as possible, or are just starting.
Fill the sink with water and soap and wash up as you cook, and let your cooking pan/pot/whatever soak while you eat so cleanup only takes a few minutes.
Hell, if you git gud enough, you can cook 2-3 meals in that time period and have food for the whole week.
Most meals should only take about 30m of actual activity, especially if you choose recipes that are single sheet pan/skillet, or slow cooked.
It could be, maybe, just maybe, and here me out here, that the comic is not the absolute, actual depiction of one's day to the second, just a generalism to get through the point. Which can be done through not too dense heads which are able to do a bit of imagination and not taking a comic literally. Geez.
I used to make time for gaming with my friends every day by sacrificing my sleep. I only realized how much it messed with my health once I started getting a full 8 hours of sleep. Now I mostly play during the weekends.
Try getting old. I used to want 9 or so. These days, I seem to just wake up after about 7 hours. I don't really use an alarm anymore. I just get up when I am awake and know that getting back to sleep isn't going to happen. Even nights after a good workout, I pop awake after about 6 1/2 to 7 hours. Never used to be this way. But, I just seem to need less these days.
A Steam Deck helps! I can lay in bed after the kid is asleep and knock out a half hour/hour session before sleep. Let’s not talk about the advisability of using devices in bed…