What’s your current efficiency and SoC ? You can multiply these two to get a sense of actual range you have. (It also depends on external factors such as headwind, temp, and elevation)
If you are on highway then get behind the truck. This should help in cd and driving at 50-55 mph should help you as well. Offcourse, turn off Heat-AC.
28mph is the max efficiency if you can turn off climate control. At least that is what Lucid told some You Tubers that did over 700 miles in a GT. Hence, 50 is better than 55.