The check on Congress is the voting booth. Can’t vote out corrupt justices.
Most members of congress could as well have life terms, as long as they don't go against those who put them in power.
Impeachment was just tried to remove former President Trump twice for serious crimes (we are not talking about lying about a blowjob here), and it failed. Twice.
In the first instance, the House prosecutors proved that Trump used extortion to try to solicit a bribe from a foreign ally that would help him politically. In his defense, Trump's lawyers literally argued that he was right to do so, because he believed it would help his campaign, and him winning his campaign was the best thing for America. Ipso facto, he can't be impeached for trying to help America. Notably, the conduct was not denied. The senate sided with Trump in that argument, so he was acquitted. Impeachment cannot be used to reign in executives who extort and/or solicit bribes, that has been shown.
Then there was the second impeachment. If ever there was a case to impeach a president, it would be one who incited an insurrection. And yet, Senate Republicans slow walked the impeachment trial, then claimed as it was held they couldn't impeach Trump because they had taken to long to start the trial. I mean, when else are you supposed to impeach a president who stages a coup and incites violence at the end of his term? Impeachment cannot be used to reign in insurrectionist executives, that has been shown.
So what good is impeachment? If it is toothless in the face of blatant proven corruption (they didn't even try to deny it) and abject lawlessness, then it might as well not even be in the Constitution in the first place. It's moot.
Some states have binding resolution. This is where the anyone can go door to door asking for signatures. With enough signatures the resolution is placed on the ballot and the people can vote on. Passage forces representatives to change laws and requirements based on the wording of the resolution. Example would be Colorado requiring legalization of cannabis while overriding the elected politician that kept voting against the legislatively pushed legalization.
Most states have non-binding resolution. This means you can go door to door and get signatures to place on the ballots for the people to vote on. The outcome of the vote has no power and is just means to perform a mass survey.
Votes that pass binding resolutions are more equivocal to, "Representatives, you must do this". While non-binding resolutions are equivocal to, "Representatives, please please pretty please can you act upon our request, we beg of you".
I would say in order to actually have checks and balance, the people must be the fourth section of government that can enact change. Ability to vote on a single issue instead of only being able to vote on a single person.
In my opinion, having binding resolution reduces the need for protests and violence to enact change. And require politicians to work together versus being extremely polarized.
But I think recent history has taught me that voting matters, and elections matter. People are getting what they voted for across the country, and I don't think there has been a point in recent history where that has been starker. A state like Colorado is often called "purple" because many issues are split down the middle there. So yeah, in some instances there's going to be a mismatch between the electorate and politicians. But at the same time, there's a big difference between e.g. California and Florida regarding how someone like me (LGBTQ) is perceived by the government. It's not direct citizen action holding the lions at bay in my state, it's the collective action of voting for representatives who don't pass legislation targeting us.
At least in theory.