And fossils all appear to change over time, there have never been exceptions to this rule. I.E. "Modern" fossils are NEVER found in locations where less modern fossils are. This is a bit harder to "prove" to the dubius than the apple falling, only one falling apple being enough to demonstrate the point. But after litterally millions of fossils have been collected from all over the world, the evidence of life changing, "Evolving", over time always holds.
There are two meanings of word "Evolution". The FACT that evolution happened is proven well enough to be considered beyond doubt among those who have seriously studied the subject. Then there is Evolution THEORY, which is the method that Evolution operates. This is what Darwin proposed by his "survival of the fittest" method. The details of this are still being worked out, but absolutely none of those details contradict the evidence that Evolution indeed happened.
My daughter studies Music THEORY in college. There is no doubt that Music exists. But the study of how music works is called Music Theory.
The FACT of Gravity you don't doubt. But the THEORY of how Gravity operates is actually quite more in doubt than the THEORY of how Evolution operates.
First, Eevidence of fossils with increasing complexity at different levels is not proof that evolution is a fact. Second, your definition of what constitutes a "theory" is a specious attempt to suggest that evolution is a "fact." True, music theory explains how music works. but your analogy does not hold. I can hear music. Music can be played. It can be heard whenever a child bangs a piano. You cannot observe life being created out of nothing. You cannot replicate it in a laboratory. The theory of evolution does not explain how "evolution" works. The theory of evolution is an attempt to explain origins.