I know what- cite a poll that rates Trump's presidency higher than the lowest half dozen or so.

You might start at wikipedia.  Siena College Research Institute, Presidential Expert Poll of 2018 there has him 10th in luck (before 2020 Covid recession) and 25th in 'willing to take risks'. Otherwise, solid number 38, 39 or forties out of 45 POTUS rated.

That poll has Trump's average at 42.6% (less luck and willing to take risks). That puts him just above Warren G Harding and Andrew Johnson.

Maxed the white supremicist score, but that was based on a survey:

Scholar surveys of diversity and racism
American Politics and the African American Quest for Universal Freedom polls (2002–2020)
Professors Hanes Walton Jr. and Robert Smith conducted a poll in 2002 for their book American Politics and the African American Quest for Universal Freedom, where 44 African-American political scientists and historians ranked presidents for their personal and institutional racism against their policies to counter racial subordination. The polls have been updated for subsequent editions of the book. The results (through Donald Trump) were as follows. Note that "white supremacist" refers to personal belief; the other categories refer to policy.

Rating of presidential racism

White supremacist

George Washington

Thomas Jefferson

James Madison

James Monroe

Andrew Jackson

Martin Van Buren

William Harrison

John Tyler

James Polk

Zachary Taylor

Millard Fillmore

Franklin Pierce

James Buchanan

Abraham Lincoln

Andrew Johnson

Grover Cleveland

William McKinley

Theodore Roosevelt

Woodrow Wilson

Warren Harding

Harry S. Truman

Dwight D. Eisenhower

Richard Nixon

Donald Trump