I guess we're a bit off topic at this point but I think the only glaring structural issue is the winner takes all voting.
> electoral collage
I'd disagree that the US got this wrong; it made a lot of sense historically. These days it arguably introduces some unnecessary inefficiency into the process but I don't think that really matters in practice. The primary objection seems to be that it doesn't reflect the popular vote, but that's entirely by design and arguably the right thing to do.
> two party system
I agree with this but want to clarify that it's specifically first past the post due to winner takes all voting that causes this. It badly needs to be fixed but why would party politicians directly vote against their own career interests like that?
Separately, political parties themselves were argued against when the country was founded but sadly they were allowed. I'd note that most (all?) western countries also got this part wrong (IMO).
> The large population makes it hard to get enough consensus to make fundamental structural improvements
This is intentional. AFAIU, the US political system was specifically designed to be resistant to change in order to avoid the failures of previous republics.
> reduces the influence of an individual vote for any national office
Things were hypothetically (AFAIU) supposed to be done at the state level (think EU) but the interstate commerce clause ended up doing wonders for that.