Had to remove 1095-A since changing to "can be claimed" caused a review error on SS number field on 1095-A.
Amazingly starting over for the 5th time worked and got it filed! Here's how with comments:
1. Before opening any other forms, went straight to 1040x and checked "2021" which only caused only the original refund amount to be transferred to Section A of 1049x.
2. Marked "File Amended Federal" and "Original federal e-filed"
3. Changed "Claimed as Dependent" and "Was claimed" to YES
This time did NOT indicate WITHDRAWAL for amount due (will get bill presumably) since a previous attempt had a message "cannot do withdrawal when refund due" because the 1040 now shows a different overpayment...
Waiting to see if accepted by IRS!
None of this previously made sense and no suggestions helped, but thank you all for trying!
Also did not save it with F10 but went straight to e-file and saved it when requested and now the efile message showed "Amended Ready" for the first time so I filed and it went through to Intuit this far for now..