During the pandemic, however, Fauci and various levels of government acted as if every hypothesis was settled science.

My impression was that they were acting as if their recommendations were made with the best available information they had at the time. Nothing about that says "settled science", and as information changed, so did the recommendations.

I tend to find the phrase "settled science" is usually a strawman -- you're basically claiming like they were acting like they already knew everything. As I recall, most statements made by various officials were couched in the usual language one would hope for: "to the best of our knowledge", "the data seems to point to", etc.