Vote for or against them in the elections provided for the purpose?

Your number is way off (435+100+more than 1 executive branch), and furthermore, if you don't follow the money that influences these actors (lobbying, revolving door, non-blind blind trusts, etc) then you don't really understand what or who is driving those decisions.

Fighting politicians is like whack-a-mole - even if you get rid of bad ones, the replacements are often just as corrupt as the ones that got replaced.

Fight the corruption first.

Exactly. It doesn't make sense to fight politicians, because they pretty much have no agency. They are public faces to the decisions made inside the system that is both influenced from outside (lobbying, et al.) as well as having its own power dynamic. If you're a honest, well-meaning, incorruptible politician, you'll get filtered out from the system at early stages. No one is going to let you take an important seat if you're uncontrollable.

That America's government does a poor job of representing American society is a separate problem. The way you solve that is by changing the voting system to proportional representation in both the congressional and presidential elections.

How can Americans be so upset at their political situation without even discussing ways in which to change it? Unconstructive complaints is just whining.

One possible solution - add more representatives to make the power less consolidated.

Another possible solution: give them only 2 trillion to spend

Devolve as much as we can. Split federal programs into state programs, then county-level programs, where the money is collected and spent on a much smaller scale.

Three steps would improve the situation(IMO): Triple the House of Representatives Term limits(12 years both house total) Repeal the 17th Ammendment