While I didn't run this much, I used to run 50 km / 30 miles a week. My "cardio" was good, but I didn't lose weight because all the running made me 1. extremely hungry 2. too tired to cook a proper meal, 3. have a convenient excuse to eat bad...

"How could I not eat a second donut, I just ran 15k!"

I was not "feeling fit", though, I believe I had low T, and I stayed relatively fat, which is not great for your organs, liver values, heart, etc.

So even if you are able to run 50K a week, you may still be somewhat unhealthy due to poor diet and other factors, and some of them can be improved by losing weight...

For #2, meal prep is a valid strategy; double up on ingredients when you do cook, put the leftovers in the freezer for later.

I was too lazy to cook a proper meal for a good while, but I would make something in weekends. Since all portion sizes in shops are catered for 2-3 people minimum, I'd always have 1-2 portions left over. I had convenient 500ml freezer/microwave containers which was also ideal for portion control. Lost 8 kilos in 8 months without actively dieting during that period.

Mind you it was also a stressful period, with a new job and stuff.