Does your g acc actually show 日本 in location? Or is it soft JP acc.

It shows japan

Hmm, have you added fake jp name and address?

I have never used gp cards, only paypal and bank, so I can't say 100% but I know I wasn't able to make any purchase without the name & address along with JP credit card number generator to 'verify' even if it obviously can't be used.

You cant use gift cards if not personally in that country, cuz its super region locked and always use your IP address, so theres no circumventing that without high techno knowledge