If you think UK politics is complicated, thank yourself that you don’t have to put up with US politics. It’s not just more complicated, but barmpot! Although we don’t have fair voting (that would be Single Transferable Vote which stops boring old MPs hanging onto seats for decades, even when they don’t live in the constituencies they ‘represent’.
In the US, there are two main parties. But other parties have almost no influence (the way the system is set up makes it near-impossible for anyone to avoid wasting votes for say Lib Dems, Greens or independents). State governeors have greater powers than our councils, but it’s also complicated . It seems everything is set up to retain the status quo as long as possible.
For instance, independent candidate Robert Kennedy Jr is very popular, but has zero chance of being elected (it will either be Biden or Trump, unless one of them is no longer campaigning by election day for whatever reason).
differences between Republicans & Democrats
The colours are a bit like our two main parties. Republicans (nothing to do with being anti-monarchy) are ‘right-wing’ and tend to go for low taxes and believe in religious education and the death penalty often (even though the low-crime states are in the northeast where there is no death penalty).
Democrats tend to be more ‘progressive’ and less harsh on issues like immigration and more focused on environmentalism. However, on election Biden revoked on a big environmental promise, which is why many would prefer to elect Robert Kennedy Jr (who is a staunch environmentalist and also wrote a children’s book on St Francis of Assisi). As part of the ‘Kennedy clan’, he is also immensely popular. But until voting systems change, it’s unlikely anything will change soon.