"mass mail-in ballots [COVID 'era']as seven Blue States do as those are subject to fraud."

Yet said fraud is extremely rare. How do you explain that? You cannot.

As for "biden received millions more votes than the very popular obama, and then four years later, about 20 millions of those 'voters' seems t have evaporated"

Occam's razor They stayed home.

The 2020 election saw the highest turnout in 120 years, with roughly 66.7% of eligible citizens voting, driven by intense interest in the election and the high-stakes political environment.

Due to the COVID-19 pandemic, many states expanded access to early and mail-in voting, which historically increases voter participation, particularly among certain demographics.

Since 2008, the U.S. population increased from roughly 304 million to over 330 million by 2020, leading to a larger pool of potential voters.

Too bad for you. Mail in voting will continue. You will just have to make sure you mail it in early this year. Maybe take a Tylenol when you try to think about it.