Agreed.  I had the same question.  The only information I found out about separately attaching it to the 2023 return as an e-file attachment was this thread.  I called into support a couple days ago to ask about it and the lady (who was very nice) also didn't know after researching it.  It seems like this would be a common question this year among tax preparers that use Intuit products to e-file and there would be a notification about it.  At the very least, I would think they'd have some info on the back end that the diagnostic isn't generating this year because Form 7203 no longer needs to be separately attached. 

If anyone from Intuit sees this, please run it up the flag pole and do a quick notification about it.  It would be clear communication, reduce phone calls into tech support, and reduce confusion.  Thank you!