You don't even need to run. Starting your day with a 15min walk has huge benefits. Maybe someday most people can actually enjoy their physical activities but start by forcing yourself to do something, similar to flossing your teeth, will form the habit and give you a taste of the positive benefits.
He stopped eating any foods with added oils, as well as anything fatty like nuts and avocados. He eats absolutely zero oil, just basic grains with vegetables and fruits. Ten years later and his doctor says, aside from the stents, he shows no signs of heart disease at all.
Anecdotal improvement aside, your statement about high carbs/low oil being unsustainable is false.
You need dietary fats to be healthy, and healthy sources like fish and nuts are often recommended by doctors and dieticians to improve cardiovascular health.
Diet and exercise recommendations work in the overwhelming majority of people who actually follow them.
This is validated by mountains of research.
The reason we have such poor health outcomes in the US is because people have such terrible diets and sedentary lifestyles which are contrary to those recommendations. And as these lifestyle choices are being adopted in other countries, you see their populations starting to have similarly bad health outcomes of the same kind (e.g., diabetes, hypertension, etc.).
All of this is extremely well-understood.
I also recommend some form of mindfulness, whether it's being fully present during a workout, or just sitting in the sun for 10 minutes in the morning.
The feeling of burnout/constant dread is a tiredness of the spirit. Physical nourishment and exercise can only provide so much. You gotta feed the soul too.
I exercise 2 hours per day, 5 times a week, and eat healthy food: vegetables, protein, no snacks, low sugar, low salt, no ketchup, no mustard, no mayonnaise, no oil for cooking, basically anything doctors recommend, I do it, and I have been doing it for the last 5 years or so.
Does it help? Probably.
Do I still feel constant dread? Yes, every single day, but I learned to live with that feeling and focus on the happiness between work hours.