We're about to find out what comes after the ACA. One week after the election, the ACA will be struck down by the Supreme Court because the individual mandate was removed. It is inevitable now after Trump packed the Court. Then, it really depends on who is elected as President. If Trump is reelected, then nothing will replace the ACA because the Democratic House will not work with him. If Biden is elected, then the ACA Act will again be made law with the restoration of the individual mandate. At least, that's what I figure at this point.
The SC won't rule on the case until summer 2021. And if it's still a problem then I expect them to at worst strike down only the individual mandate, not the entire law.
> If Trump is reelected, then nothing will replace the ACA because the Democratic House will not work with him.
I think you misspelled "because the Republicans will be unable to come up with a replacement plan, just like they were in 2018, and really every day in the last decade". The House has passed 400 bills that the Senate hasn't even bothered scheduling a vote on (much less passed their own version of, and gone to reconciliation over), and that number is
8 months old. Including, more recently, their version of a 2nd round of COVID relief. The
House is not the side that's refusing to work with the other.