The Unsupported Region notice you get is based on what you KYC/AML with them as. So if you created the account and provided your identification to show you live in India, then it will check regional availability for India. It doesn’t matter what IP address or Locale you set for your devices.
So if you’re getting the Unsupported Region notice it means you likely don’t live in one of the 19 countries that are currently allowed to link to Gemini, which are the ones listed below: