In Congress and my state, they control their own salary; however (in my state), the pay raise cannot take effect until after the next election, theoretically provided a buffer against last-minute or very large increases. I believe the same rule exists in Congress but I am not sure.

To be fair it's only a theory. I was told the same by a friend of mine who is a jurist regarding judges salaries that are high on purpose to prevent corruption. "That's the theory" he said. Western Europe.

I doubt it does much to prevent corruption. You see multi-billionaires working hard to influence tax laws to keep a few more percent of their income despite having more money than they could ever possibly spend.

I am pretty sure no matter how high the salary you can't prevent flattering the ego as a mean to corrupt someone: "It's not about the money, it's about who I am and I am important enough to them they need to corrupt me. They need me. They owe me now.". Or something along those lines.