The Wikipedia list is trustworthy, even if the US Congress is not.

So ombudsman can be for "petty" things, like the belt of my e-bike, but also for much more "serious" things like political corruption, vote scams, etc where I imagine Congress might be correct. As https://en.wikipedia.org/wiki/Ombudsmen_in_the_United_States clarifies though there are ombudsmen dedicated to agencies but also state level or even city and county level. So I imagine the more precise you are picking the right one, the more likely it's going to be treated, efficiently or at all.

Based on their relationship to Trump I'd say they were impotent.