This is why omicron was able to so easily end up with some genetics from a milder coronavirus that regularly circulates as the “common cold”, because they’re pretty much the same thing, SARS-CoV-19 is essentially just a novel cold virus that humans lacked pre-existing immunity to, and thus it was able to cause far more harm to the body than it normally would’ve. Eventually, the descendants of this wave of Covid will probably become perceived as little more than a somewhat-bad colds as we continue to adapt to its presence (and to some extent, as it continues to adapt to us, as in general it’s actually more advantageous for viruses to keep their hosts alive while still being as virulent as possible, rather than killing them. Viruses in general don’t actually benefit evolutionarily from killing their hosts).

iirc, there are H1N1 influenza strains directly descended from the 1918 pandemic virus that continue to crop up as seasonal flus, and only occasionally does another one pop up from that lineage that causes serious enough illness to be especially noteworthy (“swine flu” back in the early 2010s was actually an example of this if I recall).