To expand this a bit:
Joe Manchin (And Sinema) hold an immense amount of power right now as they are the make or break votes for the democrats. This is a problem for the Democrats as Joe Manchin is a Blue Dog Democrat who has to represent a fairly red area. Now, Joe basically doesn't give a fuck about federal-level politics at this point and has been angling towards a governorship for a while now. So pissing off his voters is a bad idea. But, if he sticks to that hard he will face some rather nasty backlash from the Democrats he'd rather avoid.
He has to play both sides.
So, he suggested a series of amendments he thinks would get him able to vote for the voting bill, and proposes a 'compromise' to reduce the filibuster down to 55 votes rather than 60. These are all 'reasonable' compromises that he knows will have exactly 0 chance of passing. Reducing the filibuster to 55 solves nothing, you'd still need 5 republicans to all break ranks and vote for a bill and the usual count of solid RINOs is 4, with 5 more soft RINOs who are very, VERY anti-Trump (put a pin in this). So, it basically would do nothing, and that means the voting bill -will- be filibustered. This frees up some basic strategy.
1: Propose 'reasonable' amendments to mollify the Democrats.
2: Then wait for the inevitable filibuster.
3: Grandstand about how tragic this is, but do absolutely nothing to resolve it.
Aaaand done. Keep that going indefinitely. All Joe Manchin has to do at this stage is continually vote for the bill to move to debates on his proposed amendments, and watch as it's inevitably filibustered. He has to make no further moves to secure his position because it's out of his hands. The only way to pass it is to abolish the filibusters. This brings us to the pin.
Manchin's proposed amendment to that is the weak link. Though he can stand firm on it with Sinema and the other two non-vocal bluedogs backing him. None of them have a good reason to change things. Even if the voting bill passed to secure their position, there is no guarantee it'd survive legal scrutiny. In fact there's a good chance it'd fail due to being rather explicitly unconstitutional. The only way to shore that up would be court stacking. So in order to sell this to the blue dogs, the Democrats would need to make the case for out and out corruption to them and... well, that's gonna be a hard fucking sell. Its a nonstarter.
So we have a case where the filibuster thing won't pass, and thus Manchin gets to do fuck and all now to retain his position. The only way this goes south is -potentially- if Trump runs. And this is likely why Trump hasn't thrown his hat in the ring just yet. Those 5 Trump Hating RINOs who voted to impeach him could prove decisive if a motion is made to reduce the number of filibuster votes from 60 to 55. Thus, Trump is remaining silent until after the mid terms.
The plan is fairly simply on the Republican side, Stall like mad till 2022, hopefully regain the Senate since the Democrats have failed to enshrine their bullshittery and without a strong anti-Trump sentiment they can't rig things elsewise. With the Senate under solid Republican control, the whole thing is dead in the water and Trump can announce he'll run the day McConnel gets the gavel.