Evolution does not claim to explain the development of the universe or how life first begun – it explains how new varieties of life forms emerge from earlier life forms.
A Scientific Theory refers specifically to a well-substantiated explanation which accounts for a body of well-substantiated facts.
People who make statements such as ‘Evolution is just a theory, not a fact’ are not using the terms correctly.
In science, theories don’t get ‘promoted’ to facts, facts are explained by theories. Theories are the ultimate goal and the ultimate achievement in the sciences of nature.