A lot of those sketches are poorly written.
I bet with a little work you could write your own.
At that price point you probably just have one dual h-bridge for all 4 motors, a single servo for the echo location sensor and some line sensing stuff.
Individually none of these are super difficult concepts to develop.
Together combined with millis() timing you could have it going with a few days or maybe a couple weeks worth of work, but you'd also understand and own the coding concepts yourself.
People will help if you try, but that's just one approach.