I had a pretty bad case of Coronavirus, had a high fever for nearly 2 weeks, but I actually never lost my sense of taste or smell! Those around me who contracted a mild case, actually lost smell and taste. Pretty odd stuff.
An initial infection via inhaling a large "initial inoculum" (viral dose) into the deep lungs (its favorite cells)? Severe case, but less impact on nasal/smelling membranes.
An initial infection in the outer nose - which is to some extent the body's evolved sample-invaders-and-contain-them zone? Definite temporary impact on smell, but a relative immune-system head-start before viruses reach the lungs, so milder case overall.
(Some health-care workers have shown repeated positive nasal swabs, but remain asymptomatic & seronegative for blood antibodies, suggesting they had a very mild infection fought-off completely in their nose/throat. Some of these have also then generated re-infection reports, but similarly mild. It seems if the body has an easy time confining the infection the 1st time, it also never bothers to create a large standing army of antibodies – but that's exactly the situation where it doesn't need to.)