Nearly every symptom attributed to COVID-19 also can be a symptom of many other more common illnesses. The loss of taste and smell is probably the least common to other bugs.
The thing is - if you have symptoms and test negative for COVID - you probably don’t have COVID. It really is that simple. Covid’s incubation period can be fairly short or fairly long - but if there is enough virus in you to trigger symptoms, you will test positive unless the test is improperly handled/processed.
Now - because of the overlapping symptoms, one could theoretically have one of the myriads of other bugs that cause similar symptoms and HAVE BEEN exposed to COVID - but the COVID itself has not manifested yet from incubation... But again - this is not a very likely scenario for most.
It’s like in africa, where they go buy symptoms to diagnose aids. They get more funding that way. I am so ready for this china flu mask crap to end.