You must remember These vehicles act just like the real ones. They DO HAVE LIMITS as far as degree of angle they are able to traverse.
Other than adding some more weight you dont really have any options.
High torqe motors and gear boxes. SLOWER MOTORS with MORE Torque.
You are having an issue that you are compounding by wanting a dragster tank. Every time your on you want to go faster.
It's a TANK, it AINT meant to go fast
Speed or Traction, you cant have it booth ways. You have also been told how to achieve either desire so it's time to do something about it for your self.
Turning the tracks around will only make the situation worse as they are a DIRECTIONAL track. It is optimized to travel in the direction it is mounted
Look up the Bulldog and find out what it's real operational limits where.