It seems to me you’d want kids exposed to COVID at a young age so they’ll have immunity going forward. I raised my kids before there was a vaccination for chicken pox. Parents would often expose their kids to other kids who had chicken pox. You knew they were going to get it sometime - and the disease is worse if you get it when you’re older.
The average adult human receiving a high viral load of a cold virus they had years ago will get it again. Zinc and vitamins and cow medicine and who knows, maybe eye of newt and ear of bat (well boiled!) may help a little, but up that viral load some more and you'll likely be hacking and coughing in a few days.
Human immune systems do better with long term naturally gained immunity to more often dangerous diseases (like chicken pox as an adult), but even that frequently fades. See: Shingles.
If Covid took out a strong % of humans in their reproductive years, eventually we might develop resistance to it, perhaps something like chicken pox. However, Covid mutates into new strains quickly enough that we might not ever catch up. Luckily, Covid would probably* mutate down in severity: The virus can't be successful in the long run if it kills too many of its hosts.
*This is widely misunderstood. Viruses usually mutate "down" in lethality if they kill too many of their hosts, but the pressure on Covid to mutate down is quite low. If "Delta" had a CFR 3x that of the original Covid, or such a new variant developed (Delta infectiousness and 3x the CFR), no epidemiologist or virologist worth a damn would be surprised.