Same Product, Duplicate ASINs, 2 different UPC

Hello. I have submitted dozens of cases to fix a brands' catalog that has all their products on Amazon. Unfortunately, some ASINs were created with GTIN exemption or incorrect UPC. The ASINs with incorrect UPC or GTIN exemption has better sales velocity than the ASIN with the correct UPC. We also need the correct UPC on the GTIN exempt ASINs to enroll in transparency program.

My attempt to update/correct the UPC on the higher sales velocity ASIN will not work due to 2 reasons

1. Error code 8541

2. Amazon's policy that "once a listing is created, it will remain with the same UPC it was created with as this would be considered a new product"

My desire

1. Update duplicate ASIN with correct UPC

2. Merge duplicate ASINs

Example 1

ASIN1 correct UPC (no sales)

ASIN2 incorrect UPC (lots of reviews and sellers)

Solution Desire

1. update ASIN2 to correct UPC (this results in error code 8541) since no 2 ASINs are allowed the same UPC, despite the thousands of listings on Amazon with this issue

2. merge ASIN1 with ASIN2

3. Enroll in transparency

Example 2

ASIN1 correct UPC

ASIN2 GTIN exempt

Desire:

Update ASIN2 to have same UPC as ASIN1, then merge both ASINs

I need a moderator to help with this issue. I do not expect a solution but worth a shot. Please do not give me the generic answers. I also dislike that once the word "merge" is mentioned, that is the only thing that a seller support associate looks at and provides a template/generic answer that merging cannot be done with different attributes. I am aware of this. I need help in getting the attributes to be the same before any merging is done. However, EVERY associate is fixated on the same answer.