I'm starting my Starship program the same way SpaceX did: with a Starhopper test platform. I learned many useful things from this exercise before I invest in real hardware for the Starship build:
With control via thrust vectoring (roughly) figured out, the next step is to translate what was learned on the Starshopper to a Starship. The Starship will hover nearly the same way, but with the addition of fore and aft lifting surfaces that enable control in the descending "parachute" mode. If that goes well, we may also need to build a Super Heavy booster to launch it with.
For flight control and stabilization on this project, I'm using my open-source flight controller that is Arduino-based and runs on the Teensy 4.0 with MPU6050 IMU: Project Page