For many reasons, the fossil record is not that complete. But that is how evolution works. All the fossil record shows is essentially snapshots taken at different times.
It’s like the growth of a baby: you don’t see day to day changes. But if you look at a newborn picture, then at a picture taken at age two, and another at age 15, they are all clearly different.
And, as I said, all science is an art, no matter how it is presented in the popular media. Many experiments do not give clear cut yes or no answers; they give shades of grey, leaving it up to the scientist to examine the data and decide what the result really is. Scientists of varying levels and types of experience might give very different answers for the same data. So, yes, as much as we would like to believe that science is completely objective, it is not.
It’s not at all like the growth of a baby. A baby starts out human and remains human at every stage.
All science is not an art. The soft sciences are, hence the term soft.