The biggest thing for somebody like that is avoiding deficiencies. Given that workload, given that lifestyle, you’re not really trying to enhance performance. Maybe you will, at certain points of the year as you train for a marathon or something, but day to day you should be looking at your diet. For the most part, you can avoid deficiency by eating a wide variety of fruits and vegetables, consuming enough protein from whole food sources and then meeting your energy requirements through your typical foods.
Vitamin D is still something that jumps out during the winter months. I do think it is a worthwhile investment for most people, and it might only cost a tenner over the counter to cover a few months.