Frankly, re-opening HC.gov is actually one of the simplest and most obvious healthcare-related executive orders Biden could give at the moment. Now that the starting/ending dates are known, it raises one other important question.
UPDATE 4/03/21: I've confirmed with a highly-trusted source that this isn't happening...at least not before the Supreme Court issues their ruling, anyway.
As noted below (scroll all the way down), it appears that a $1.00 penalty would be too small to make the reconciliation cut, which means the only way to #MootTheSuit via reconciliation would be to change the mandate back to an amount large enough to have a significant impact on the budget...which presumably means several hundred dollars.
I mean, if they're gonna do that, they might as well just restore it to the original $695/2.5% of income while they're at it.