examples of US party rebels?

You could look at how Joe Manchin in particular has helped screw over Biden in the US

ahh, thank you! That was the only one I could vaguely remember but couldn't recall the name

sorry, I've accidently put this on the wrong forum and don't know how to delete it or move it??

Just to drop my own thoughts in here though, essentially I'd say there are two main differences in characteristics that explain why the US tends to be more rebellious than the UK.

First, in the US, the party that is in government is decided by the party of the president, who is elected separately from either house of Congress. It's possible, for example, that the Republicans have a majority in both the House of Representatives and the Senate, but there's a Democratic president, and the Democrats would still be in government. In the UK, the government is dictated by whoever can control the House of Commons (usually the House of Lords has too many independent 'crossbenchers' nowadays to also be controllable, but it's enormously less important than the US Senate). That means that if you're overly rebellious in the UK as an MP from the governing party, and vote against the government at crucial moments, like a budget, then it's possible that the whole government will fall and the other lot will get in. Rebellion doesn't have the same existential consequences in the US.

Second, the UK PM has much more power of patronage than the US president. In the UK, ministers have to be in Parliament (usually MPs but sometimes peers), and the PM picks their ministers from among their party's MPs and peers. In the US, ministers aren't allowed to sit in Congress and have to resign from Congress if they're there already, so usually only a small number get chosen from Congress, and those that do have to resign their seats. That means that rebelling in the UK makes you much more likely to miss out on the government promotion you want (or if you're a minister, if you rebel as an MP you have to resign your ministerial job). In the US, you're probably thinking less about getting a ministerial job in the near future and have less to lose. It also means that in the US the government doesn't have a 'payroll vote' like in the UK – that's around 100 different government ministers who are also MPs and who have to vote with the government or get sacked.

If you look at what has just happened - Manchin & Sinema destroyed Biden's entire agenda. There is nothing he can do about it because (a) he's a pathetic, barely functional human and (b) whoever is controlling him insists on putting forward all these enormous omnibus bills. There is no way Manchin and Sinema can sell these back home, and I think part of them actually wants what is best for their constituents. They were left with nowhere to go so they told Biden they weren't having it, and don't want to look like the depraved hypocrites that the rest of the party are when it comes to the filibuster.

As senators, the president has nothing to threaten Manchin & Sinema with. The left of the party already hate them, and have already set their followers on them, trying to harass and attack them in public. Biden has no presence and no authority - after there are people chasing Kirsten Sinema around in public, what can Biden possibly do to try and get her into line?

As for Manchin - at the 2020 election, West Virginia went 68% - 29% for Trump. Manchin has over 60% support at home, whereas Biden has less than 30%. There is no way that Manchin can be threatened by Biden.