It obviously irrelevant whether the law was bipartisan or not, and the Supreme Court never "affirmed" the law--it denied a preliminary injunction.

As to upholding laws passed by Congress--just two days ago, Biden did his last round of student debt forgiveness, bringing the total up to $188 billion.

I’m not trying to “both sides” this. I’m just saying that the standard you’ve articulated for how promptly the president needs to act on a law like this isn't the standard we apply in practice. The government tries to reach deals like this in lieu of enforcement actions all the time.