One problem I can solve, the other I can't.

To keep the 4 wheels on the ground, and the hood and roof towards the sky, use throttle control. Don't try to race yet. You aren't there. Let your objective be to NOT wreck. No matter how slow you're going, just don't wreck. Everybody started out as a novice and there is no such thing as a "born" RC racer. They are developed over time.

My grandson had the same issue. He wanted to "race" before he could drive. It's not the course's fault, or the truck's fault. It's the "driver's" fault 100%.

You'll get there, but patience is a must!! Remeber: Don't wreck no matter how slow you have to go.