You have a point that Clinton was pretty good, and was probably the first showing of the Republicans becoming obstructionist and never relenting since.

The Democratic Party has control of the Senate in name alone. Sinema and Manchin do not toe the line and have effectively threatened to even switch parties if they aren't taken seriously. The "control" the Democrats have had in the past four years of any branch has been teetering on the edge of a pin. They basically had enough to just stop harmful Republican policies that would have been passed instead. The one thing Republicans do better than Democrats is to simply back each other up no matter how corrupt one of them might be. Trump probably could have shot a person in broad daylight in the middle of fifth avenue and Republicans would ensure that nothing happened.