[slyall]

The problem is the US is still running off best practice from 200 years ago and is famously hostile to change or copying another from other countries.

Any change is also going to disadvantage the two current parties so they will be hostile to it. Which with the hard-to-amend US constitution makes things very hard to change.

Some form of proportional representation or maybe STV in multi-member districts is actually what you'd do. Single member districts with fancy voting systems just gets you a token 3rd party representation.