Are you aware of how math or politics works? The Democrats have the White House and mathematical majorities in both Houses of Congress. That is control of congress by definition. Nothing you can write changes that fact.

Whether all Democrats vote with the president is a matter of politics. LBJ understood how politics works. You go to Joe Manchin and say, "You want funds for your state? You better vote with me. You want my Justice department to ignore how your daughter got rich extorting money for Epipens? You better vote with me."

Votes aren't cast in fucking stone. Barack Obama used to use that same lame-ass excuse for not doing things he didn't want to do. It was bullshit then, and it is bullshit now.

If the leading Dems wanted to end the filibuster, they could do it. Change the laws on Gerrymandering too. Add Supreme Court justices. All legal. Not easy, but they don't even fucking try, because the US has one major political party with two wings, the Ds and the Rs. They both take money from the same donors and have since Bill Clinton started his third way corporate sell-out shit in the 90s.