The evil ones keep outing themselves.
7 % of Republicans did not flip; they were flipped by voter fraud.
There is simply no way for anyone to legitimately know how Democrats or Republicans voted at an individual level. In a precinct with 1000 Republicans and 1000 Democrats a 900 to 800 win for Trump could be because 900 Republicans voted for Trump or because 800 Republicans and 100 Democrats voted for Trump.
It is possible that some people who voted for Trump in 2016 may have voted for Biden in 2020. Maybe some Democrat really disliked Hillary Clinton, but thought Joe Biden was acceptable as an alternative to voting for a Republican. Or maybe the 2016 Trump voter died in 2019 and some ballot harvester marked and sent in their ballot.
These articles claiming people know percentages of voting based on party registration are really just relying on hunches, guesses, and occasionally survey data of limited accuracy.