I found out that you can transfer the gift card amount to your bank account but you need to pass full KYC.
How? AFAIK, you can not ever transfer your GC balance to bank account. Please note that, Amazon Pay balance can be loaded using bank account as well. You may transfer that money back to your bank account again.
I am aware the max you can get as a gift coupons is 5k as I recently made a purchase on Bitrefill.
No. 10k. Check
https://www.coinsbee.com/en/Amazon-bitcoin.