Tire Truing
 

I read many times that on new tires the first 1000-2000 miles drop mpg. Later the mpg picks back up. With enough money, would tire truing help those first miles? Would it help all miles?

Tire truing is shaving off the high points of the tire runout so the tire is dimensionally round. That used to be a common fix for tire vibrations that weren't fixed by balance. There's a reason why this is rare today.

So, No! That is not going to solve an MPG problem.