That link shows higher support (for popular vote) from Democrats than Republicans in every data point on the graph: 2000, 2011, 2016, 2019, and 2020. Partisan support has not flipped in at least 20 years.

What "flipped" is that it went from overall < 50% to > 50%.

The public's opinion is irrelevant, both parties will continue propping up systems that prevent any other competition from having a shot.

Do you really trust these polls ?