Everyone is different, there’s no doubt that walking is beneficial for your health and you should try to walk a bit every day.
But I wouldn’t try to hit a daily goal, or certain amount of minutes. Just walk for how long you feel like
I know it's just gamification of exercise, but if it works, I'm all for it.
This is for the vast majority of America where a 6 block trip to the corner store is considered driving distance.
If I didn't make it a 100% conscious "chore" to do every day when I lived in the suburbs, it was quite easy to go an entire week without walking more than a few hundred outdoor feet in total.
In the city it's far more likely I'll be walking to get something done anyways, so it's easy to take the long way home for some extra steps if I've been in front of a screen too long lately.
Walking is the easiest most consistent weight loss method. The do Physical Activity Thing X times and metrics like BMI are aggregates for the population meant as generic advice (some doctors can't do math without a calculator sadly).
The gist of the advice is always to figure out your base metabolic rate and roughly how many calories you lose per steps/hours of walking. You can derive this experimentally for yourself by doing and eating the exact same thing for a few days in a row. You just need a good enough scale and a spreadsheet.
This drifts over time with your age and weight, so repeat the experiment occasionally. 5000-10,000 is the target range, maybe that's how they got 7k.
It doesn't matter if you hit your number daily or average it out weekly, as long as you get your steps in the calorie deficit occurs.
Exercise is best used to build muscle mass and is not very effective if the goal is a caloric deficit. You could run, some people love doing that, but most aren't able to do this consistently enough - and the more overweight the more injury prone.
Walking works just as well as high intensity cardio it just takes proportionally longer. You're paying for your extra weight and lethargy with time. However, everybody (who can exercise at least) can do it, and it works.
Going from sedentary straight to beast mode rarely works.
And most people are in fact overweight. Walk for a month or two to shed weight, improve mood, and form good habits - then progress onwards from there. Maybe throw in pushup sets every mile or get down to the park with the bars, 'etc.