Remove Country from Checkout

Hello,

I’ve managed to remove some fields from the checkout via two functions:

/*Make fields from Checkout optional*/
add_filter( 'woocommerce_default_address_fields' , 'custom_override_default_address_fields' );
function custom_override_default_address_fields( $address_fields ) {
     $address_fields['company']['required'] = false;
     $address_fields['country']['required'] = false;
     $address_fields['address_2']['required'] = false;
     $address_fields['city']['required'] = false;
     $address_fields['postcode']['required'] = false;
     return $address_fields;
}

/* Remove fields from Checkout */
add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );
function custom_override_checkout_fields( $fields ) {
     unset($fields['billing']['billing_company']);
     //unset($fields['billing']['billing_country']);
     unset($fields['billing']['billing_address_2']);
     unset($fields['billing']['billing_city']);
     unset($fields['billing']['billing_postcode']);
     return $fields;
}

Nevertheless, when I try to buy something, I get an error. If remove the “unset” for country, it works.

How can I fix this? I only ship in one contry (which is default in WooCommerce config and appears as default).

Thanks