hard to follow, but have you reviewed BOTH transcripts (since you filed Separately?)
what is the Balance on EACH transcript. if those balances are both zero, then no wonder there is no money coming to you.
if your husband received his refund very quickly that should have zeroed out his balance, so why do you believe some of the w2 withholdings was not used????
if you were changing line 12, did you enclose the supporting documentation as required by the instructions?
https://www.irs.gov/instructions/i1040x#en_US_202301_publink11362hd0e2449
"If you are changing your withholding or excess SS/RRTA, attach to the front of Form 1040-X a copy of all additional or corrected Forms W-2 you received after you filed your original return. Also attach additional or corrected Forms 1099-R that show any federal income tax withheld."
