There is nothing Constitutional about the filibuster either.
It’s a Senate rule, and the Senate and House are empowered by the Constitution to make their own rules.
There is nothing in the constitution about filibusters.
The filibuster rule is a rule of the Senate procedures. The constitution indicates that each House of Congress sets their own rules. Those rules can be changed at any time.
The constitution calls for a 2/3 vote, or super majority, for some particular situations. Among those are ratifying treaties, approving a constitutional amendment, and override of a presidential veto. Otherwise, a simple majority vote would suffice under normal circumstances.
The founding fathers envisioned that the Senate votes would be equally divided sometimes, which is why they provided for the Vice President to be the tie breaking vote if needed.
The point is, the founding fathers didn’t envision that you would need a super majority of 60 senators to approve most matters. They envisioned a simple majority, with exceptions such as I’ve noted about, which do call for a super majority.
The filibuster, though not rooted in the Constitution, probably did serve a useful purpose back when the Senators actually were elected by their state legislators. When the States were actually sovereign the Senate acted as a check on the Federal government.