Yeah I can vouch for Shell being the most expensive in most of N Texas region.
Throughout the years I’ve noticed the most expensive gas brand can vary by region. Chevron is usually 2nd most expensive where I live but driving east to LA, AL, or MS, Chevron is priced as one of the least expensive options. I’ve read many people say ExxonMobil is the most expensive in their area but around me it’s one of the cheapest. Valero is by far the cheapest branded gasoline in my region.