Wrong Billing Information in WC_Checkout->get_checkout_fields(‘billing’)?

Update Your get_checkout_fields method with parameter billing_country
so it will look like
$fields = $checkout->get_checkout_fields( 'billing_country' );
Documentation:
https://docs.woocommerce.com/wc-apidocs/source-class-WC_Checkout.html#197-281

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