Are mutations part of the "engine" of evolution?

I find science very interesting. I was doing a lot of reading on the common mechanisms of genetic mutation. This explains how the mechanisms actually provide examples of a loss of information rather than the creation of new information necessary to explain molecules-to-man evolution.

In evolutionary theory, mutations are described as the mechanism that fuels the engine of natural selection, creating new organisms as a result. However, the vast majority of mutations are either neutral or cause a loss of information in the genetic code of an individual.

Evolution teaches that mutations have accumulated over millions of years to increase the complexity of organisms on the earth.

The Bible teaches that, as a result of Adam's sin, all of creation is in a downward slide-including the genetic information that is in every living cell.
The law against marrying close relations was not given to Israel until Leviticus 18.
Up to this point, the accumulation of genetic mistakes was apparently not significant enough to cause genetic disorders in the offspring of  close family members.

Today, with thousands of years accumulated genetic mistakes in the human gene pool, intermarriage would be much more likely to produce children with genetic disorders. So it seems that the explanation of a genetic degradation since the Cause of Adam actually fits the evidence better than the evolution model of increasing complexity.

https://www.youtube.com/watch?v=-d-J974AlF0