HIV and coronaviruses are completely different and can't be compared.

HIV is clinically a mild virus and doesn't cause any severe symptoms by itself. It is only when HIV becomes AIDS that it is dangerous, but then again, the symptoms are not caused by HIV/AIDS itself, but by the lack of immune cells caused by AIDS. You could have HIV forever and not even notice it if you were in a vacuum as you say :)

We can't know how severe Omicron will be, but let's hope it just becomes a cold. As OP said, the most enduring parasites (viruses are categorically parasites), are the ones that don't kill their hosts. This is not only true for viruses, but all kinds of parasites.