Nice to see the robot in action. Seeing the videos it seems like there are 2 big issues.
The wheel is slipping and not able to find a good drip. Changing the wheels will solve the issue.
It’s very clear that the torque of motors is not enough. That’s the reason it’s not able to take turns properly. I don’t think hobby project motors would be sufficient henceforth. We’ll have to move on to industrial grade motors.