Tinnitus , I think you are right that herd immunity may be...

Tinnitus ,
I think you are right that herd immunity may be impractical for nations as whole.
Sweden`s rate of infection has again risen since August though deaths are lower.
Perhaps achieved by small, dense populations as below.

Around 57% of people across parts of India's financial hub of Mumbai have coronavirus antibodies, a July study found, indicating that the population may have inadvertently achieved the controversial 'herd immunity' protection from the coronavirus.
A survey of 6,936 people living in three Mumbai districts found that 57% of the people tested positive for coronavirus antibodies, the proteins produced by the body's immune system to fight off disease and an indicator that a person has been infected by and recovered from COVID-19, the disease caused by the coronavirus.

Immunity may be increasing in that people are being infected with covid 19 in second waves at nearly the same rates as first but a much smaller percentage are being hospitalized or dying.
Better treatment , changing virus severity or a level of immunity preventing worst outcomes?