This is a really unique idea for a tycoon game and the combination with racing gameplay is actually so good! I really enjoyed racing my time and building mazes is a lot of fun too. Honestly, most of the feedback I have is fairly minor things. The movement during race mode felt a little too slippery, a little more friction on the player would make it feel more natural for me.
For building the maze, it would help a lot to have your selection be highlighted more or even have the placement preview show what the item is, as I had a hard time realizing if I had selected the correct hedge or not. I would also generally recommend using something like Q/E to rotate objects instead of a single button like R, just so you can rotate in either direction. With just one button, if you accidentally overshoot what you wanted then you have to go through all the rotations to get back to it.
That said, these were all minor things. The overall concept is fantastic and the music has a real carnival/arcade-vibe to it which fits the game perfectly. Nicely done!