I’m a younger millennial. I was still pretty young during Bush jr term 1 and while there was certainly distrust of Cheney and Bush there was a general positive note towards the actual office of the president and a congress that while slow still did things. I hadn’t learned about Newt’s fuckery nor really understood Bush v Gore. Then there was Iraq and it took a long time before we heard about the lies used to start the war. Then Obama was overall a positive influence on the presidential reputation(deservedly or not is debatable). Congress (at least Rs) certainly lost much of my trust under Obama with the shutdowns and nominee holdups. This is when I started paying more attention. Then, of course Trump made any trust in the office 0 (if not negative) and Rs lost all trust from the repeated hypocrisy and plain evil and of course the impeachment debacles. Biden was improving trust in the office of the president at least somewhat before Gaza. Congress on the other hand (Dems included now because of Manchin, Sinema, Feinstein, etc) has lost any remaining trust I had.

I can’t speak for others but while I generally always disliked congressional representatives I naively had faith in the institution overall for longer than I should have.