If you want to disable payment gateway based on Cart total and show only specific Payment method if cart amount higher than specific amount than using country in WooCommerce filter woocommerce_available_payment_gateways you able to easily apply in your WooCommerce wordpress website
add_filter( 'woocommerce_available_payment_gateways', 'wdo_filter_gateways', 1);
function wdo_filter_gateways( $gateways ){
if ( WC()->cart->prices_include_tax )
$cart_contents_total = WC()->cart->cart_contents_total + array_sum( WC()->cart->taxes );
else
$cart_contents_total = WC()->cart->cart_contents_total;
if($cart_contents_total