I struggeled before with the afternoon low as you describe. After i tested the keto diet and intermediate fasting i understood how to avoid it.
its extremely easy. Dont eat carbohydrates while you are working. Just stay to proteins and fat. A little bit of carbs can be fine, like a small salad, but avoid bread, pasta, rice, potatos. Anything with alot of carbs.
When you get home and are finished with the day, you can eat carbs again.
My buddies experience the same as me. I would say give it a try for 3-4 days and see how you feel.