https://www.amazon.com/gp/product/B086KKT3RX?_encoding=UTF8&pf_rd_p=517bbe37-6c4a-4bb2-b6c7-46b7e820b3e0&pf_rd_r=AZTT8WQBYM6FMT2YPV9Q

Use this link and enter the balance of your gift card where it says "Other". Then add the gift card as a new credit card payment method. Pay with the new payment method and you've effectively transferred the gift card balance to your Amazon account

https://www.amazon.com/dp/B086KKT3RX