You have not brought any evidence to the table. If there is a study that says SARS-COV-2, unlike the majority of (all?) viruses and all coronaviruses that results in immune response sufficient to clear the disease that then immediately dissipates, I'll certainly accept the premise.
Until then, a preponderance of evidence points (or suggests without proving conclusively) otherwise.
> That's crystal clear, but it doesn't align with your opinion that this is just like the flu in seriousness.
That is not my opinion. My opinion is that it's milder than the flu for young people (it is) [1], and much worse than the flu for older folks (it is) -- no citation needed, I assume. To suggest otherwise would be to ignore the evidence you claim to hold sacrosanct.