For years on end? When Covid-19 has been around for barely a year and has been pandemical for seven or so months? If you bothered to actually read up on the sources I used, both of which mirrors what the medical community currently consider long term covid, you'd see that they are discuss persistent or recurring symptoms after the infectious period is over.
Once again you also show that you don't know much about medicine (which I arguably don't either compared to actual doctors). You don't need to be 'very sick' to have a persistent cough, reasons for that can be anything from polyps in your throat, irritated vocal chords, sensitive throat, allergy, minor lung issues or just simple vestigial symptoms from a cold (young children notably can go coughing for months after a common cold, my youngest son has had a nasty cough for four weeks and it is still going strong despite him being free from other cold symptoms for three weeks). Recurring fever is more uncommon but is a sign of long term covid. So we can tell that:
A) You need to learn what a subjective symptom is. A subjective symptom is one that can not be measured or monitored by an outside party. These include fatigue, nausea, muscle pain etc.. Basically any symptom which can only be self-reported. The advanced course here is that some symptoms can be subjective in some stages but objective in others. Anxiety for example is inherently subjective but once it crosses a certain threshold it becomes observable due to motoric agitation, sweating, increases in blood pressure and pulse etc.. It still remains subjective because the severity of anxiety is largely dependent on the person who suffers it (pain works very much the same way).
B) Any symptom which can be measured or seen is an observable symptom. If you cough, have a fever, a runny nose or bleeding gums that can be observed and is thus not subjective. Hence if you are coughing for weeks or months on end after Covid-19 that's not subjective, that's objective because it can be observed that you do.
So please just stop making stuff up about things you know nothing about. Your definition of subjective is inane and not what subjective actually means when discussed in medical, nursing or healthcare terms.