Congress should be proportional, preferably MMP* since it retains the personality of voting for your representative while also ensuring the legislature most accurately represents the desires of the populace, and the president should be IRV. IRV isn’t perfect, but it’s easier to understand and motivate than Condorcet (which has its own problems).
This will never happen.
Arguably keep the Senate rules, since giving smaller states a bit more of a say is probably good in at least one house of the legislature, but move to IRV for the Senate seats.