You need 60/100 votes to control the senate, which they did not have, so no, they didn’t hold the senate.

With a simple majority, they can change the rules of the Senate so that a simple majority will get a bill passed. The filibuster is not in the Constitution.

Manchin and Senna refused to do that, as the most conservative democrats in districts trump won by double digits. Thus they did not have the votes.

We are probably about to see that in action

Can you elaborate? Genuinely curious!

sure: just because you barely have a majority, does not mean you can do anything you want.

Edited original comment to be more productive.