Why is it that the President will have usually Limited Influence over the Supreme Court?

-The Appointment Process must go through the Senate if any Vacancy occurs in the Supreme Court -The Justice, even if it's the President's Top Nominee, will not necessarily align in a way in the President's way. Presidents thus try and alter the Ideological Balancer of the Supreme Court, therefore. Trump had replaced the Liberal Ruth Bader Ginsburg with a more Conservative Amy Coney Barrett, but Biden had also managed to appoint Ketanji Brown Jackson to the SCOTUS as well