After you file

if you need your refund now, e-File and hope the IRS will handle this and send you another refund later.

Otherwise, you may have to amend later.

That is a simple thing -- well simpler thing than before -- once e-File of 2020 1040-X is open.

 

It's quite possible the IRS computers will adjust right away since the law is now in effect, and that will be that.