I'm not sure what point you're arguing (I can never tell with you, because you always reply "Not my point" when given information that appears to contradict your premise), but some basic numbers on polio would be helpful here.
90-95% of polio infections are asymptomatic. Less than 10% cause a mild viral illness that resolves without sequelae. (Note, different sources I'm using report different numbers here). About 0.1% of all cases of polio will result in meningitis, and if this spreads to the spinal cord, it causes the flaccid paralysis known as poliomyelitis (what most people actually mean when they colloquially say "polio"). Among those who develop poliomyelitis, the mortality rate is about 5-10%. So, at most, the case fatality rate from polio infection was about 0.01%. About 2/3 of the cases who develop flaccid paralysis never recover their full strength, so I estimate that means about a 0.06% case rate of permanent paralysis of varying degrees of severity, ranging from minor, regional muscle weakness to complete global paralysis requiring permanent ventilatory support (I suspect most who were fully paralyzed didn't stay alive very long, so the surviving numbers probably skew towards regional muscle paralysis).
Prior to vaccination, there were about 13,000-20,000 cases of poliomyelitis reported yearly in the US. The last case that developed from purely domestic sources was in 1979, and the last imported case was in 1993. Thanks to widespread vaccination, the polio virus is effectively eradicated from the US and all but certain countries in Africa and Asia.
So, once again, I'm not sure what your intention was with the statement "polio=Covid isn't equivalent", of which I agree. Based on the raw numbers alone, in any given year of polio's existence vs the 18-20 months COVID-19 has been with us, the latter has been much, much worse.
