If you want herd immunity, just let people live their lives, thats the fastest way to get there.... idiot.
Herd immunity against any disease has never been achieved by letting the disease spread uncontrolled. It has only been achieved through public health measures, mainly vaccination, but also measures such as masking and social distancing.
Furthermore, herd immunity does not protect individuals. What it does is decrease the number of susceptible people than a contagious person might encounter, thus inhibiting transmission. The level of herd immunity needed to interrupt disease transmission is a function of how contagious the disease is; for Covid-19, at least 60% of the population must be immune to inhibit transmission.
The idea of letting Covid-19 spread uncontrolled until "everyone" has had it is deadly: assuming 60% of the US population catches Covid-19 at the current death rate, that would doom 3.5 to 4 million people to death (plus tens of millions of survivors would have long-term respiratory, cardiac, and/or neurological issues). That would be a HUGE jump in the annual death rate; 2.8 million died in 2019, the most recent year in which data has been analyzed.