That's so interesting. We do a mostly vegan diet, and I would say on average, lunch takes about 5 minutes total and dinner maybe 5-10 minutes prep time.

Grains, beans/llegumes/pulses, nuts, seeds, fruit and vegetables.

(we do also have Salmon 2x a week and omelettes 2x a week).

I think the key is eating simply. Steam veggies (or roast or bake in the oven), beans in instant pot (or canned!), I do a microwave omelette in 2 minutes, etc.

I have maybe 3 or 4 different sauces I make that keep for a week, so that's a little more prep time. But I have found for decades - if you keep it simple, you may end up spending a total of maybe 1-2 hours (prep time) a week with food prep.