If your goal is to get there faster, CFI is the way to go. But you have to factor the time it takes to get yout CFI compared to starting Part 135 right away. I know some people working some really ****hole Part 135 jobs doing UPS feeder routes. Fly to some city in the early morning, spend all day in a hotel, fly back at night. Gone from home over 14 hours a day, get maybe 3 flight hours total. It will take them at least two years to time build.

Whereas I easily got 1000 hours in a year as a CFI/II and am a much better pilot for it.