This chart shows that the 4 trillion you state is wrong, and that the number you are stating, is for Biden's first two years, and those must fiscal years, not calendar year.
Donald Trump Added Twice As Much to National Debt as Joe Biden: Think Tank
Former president Donald Trump approved almost twice as much borrowing as current President Joe Biden during his four years in office, according to the Committee for a Responsible Budget (CFRB).
Trump, who presided over the federal government from 2016 to 2020, approved $8.4 trillion in new ten-year debt. But incumbent president Biden, who defeated Trump four years ago, has approved $4.3 trillion in new borrowing, said a new report by the committee.
https://en.wikipedia.org/wiki/Committee_for_a_Responsible_Federal_Budget
The Committee for a Responsible Federal Budget (CRFB) is a non-profit public policy organization based in Washington, D.C. that addresses federal budget and fiscal issues. It was founded in 1981 by former United States Representatives Robert Giaimo (D-CT) and Henry Bellmon (R-OK), and its board of directors includes former Members of Congress and directors of the Office of Management and Budget, the Congressional Budget Office and the Federal Reserve.[2]