Can't change my App Store region from UK to Russia with error

Hello, I've spent hours searching different so named apple support sites and didn't find any helpful information.

The problem. I'm unable to change my istore region from UK to Russia. Basically every time when I try to update/change my payment method I get http errors.

1. I am unable to set mobile payment, because this option only available for providers Beeline and MTS
2. Unable to set payment method to "None". I get API error that payment is not supported by the store. Error code "-363582580". Obviously you only see this in the debugger, no errors displayed in the browser.
3. Unable to set payment method to Apple pay. This just doesn't work for no reasons. This option is not available in the browser, only on a mobile phone.
4. None of credit cards are regarded as valid for obvious reasons.

Kindly ask you to guide me on the issue and possible resolutions. Is it possible to change the account region?

[Re-Titled by Moderator]

Original Title: Unable to change my Apple Store Region