Funny, every year people say "I had the flu". or "I caught a really bad cold" based on their symptoms, and nobody questions it.
Anyway, loss of smell in coronavirus is not the same as loss of smell with colds and flu. With colds / flu, it is due to blockages in the nose. When I lost all sense of smell and taste for 3 weeks (I ate raw garlic, sniffed curry powder, and countless other things, and could detect nothing at all) I had a totally clear nose. I had no blocked nose, no sneezing, none of the symptoms you get when you have a cold or flu) and I have had a fair few of both in my years).
So, even though I do not have a piece of paper to prove that I caught coronavirus, I am certain that I had it. There is no other explanation - it was not a cold or flu, I know that for sure!