temmink
I think Spotify blocks the usage of foreign credit cards (ie, non-Indian Credit cards). A way to circumvent this is by using gift cards. You can buy them from Amazon using the same credentials as your local Amazon account. Then it's easiest to gift them to yourself, eg, this: https://www.amazon.in/Spotify-Premium-Standard-3Month-Card/dp/B09Z6ZDKZ6
There is a limit on how many vouchers you can redeem per day (I think it's four per 24 hours) but just redeem the remaining cards the next day.
To redeem the gift cards in your account you'll have to login using an Indian VPN and then change your location. Once your location is changed, deactivate the VPN again. Then redeem the vouchers (6 3-months vouchers would give you 12 months of duo and 10 months of family). After reaching the daily limit wait 24 hours and redeem the remaining vouchers.
Once all vouchers are redeemed you can switch back to your location.
What do you want to know? That you can use a VPN to fake your location to get a different price for a subscription? Or which county is currently the best (India has decent prices)? How to get the gift cards that you redeem in the account (Amazon, eneba, ...)?
StrongBox is just a client that uses keepass databases. I think it integrates well when using Apple devices and you can still use your databases on other platforms.