They failed to actually achieve 'herd immunity' and did not avoid the eventual virus death toll:
https://www.news.com.au/world/coronavirus/global/sweden-cris...
By comparison Finland, it's neighbor took a much stricter approach and never reached the same level of death.
Finland: 931 deaths at 168 per million with a 1.0% death rate.
https://epidemic-stats.com/coronavirus/finland
Sweden: 14275 deaths at 1406 per million with a 1.4% death rate.