Correct. IRS will have to issue refunds.
But they will wait to see if it is appealed, and what those decisions are (if any). That will take some time.
In the meantime, it is unconstitutional and should not be paid.
If it is overturned on appeal, then SCOTUS will overturn that and it will be unconstitutional.
If it is affirmed on appeal, SCOTUS will not hear the case and that will be that.
Either way, it is dead. But it will take some more time before IRS issues refunds.
But I wouldn't pay anymore, and if they send a letter, refer to that ruling as justification for not paying, and demand a refund of any amounts already paid.