You can only change the Google Play country setting once a year. You can only change it if Google determine you to be located physically in that country. Based on my testing, the only combination I could use to trick them was:
* no SIM in the phone
* Wi-Fi connected to another phone's hotspot which is VPNing to the desired country
* GPS off
* payment method in the desired country
That way Google have no way of knowing you're not actually in the desired country. Just certain parts (even including a SIM card in roaming originally from desired country didn't work) weren't enough.
- Billing addresses for Google Play
- Wifi and cellular networks seen by your Android devices
- IP addresses and other identifiers of all devices you used to access Google services (mobile and web)
- GPS metadata in pictures uploaded to Google Images and Drive
- Documents with addresses such as bills in your Google Drive and Gmail
And probably much more that I can't think of right now.
The Google Play store country however can be changed once per year, but you need a valid billing method originating from this country.
- Installed Fake Traveller
- Set Fake Location App
- Set location to Sydney, Australia
- Open Play Store
- Search for ANZ Shield (Australian banking app)
Result: App not available in my region :(