And the diff between sedentary no exercise and 1626 TDEE and sedentary with vigorous workouts 3 times a weeks of 2089 is 463 more calories you can consume.
I've never been a fan of this "exercise so you can eat more" view of life. MyFitnessPal looks more like MyOverEatingPal.
Running 6 miles at 6 mph three times a week may add an average of 463 calories a day to your expenditure but you have to watch out for reductions elsewhere - like falling asleep in the chair afterwards.
Some studies don't find an increase in
overall daily calorie expenditure when comparing exercising subjects with non-exercisers, others find an increase in eating that neutralises the exercise. Caveat Exerciser (with apologies to the Romans).