Prevent WooCommerce from Selecting Default Payment Method on Checkout

add to footer.php or checkout specific template file

tested on WooCommerce v5.2.2 | WordPress v5.7.2

if using a version of jQuery older than 1.6 change
jQuery('.wc_payment_method > input').prop('checked', false);
to
jQuery('.wc_payment_method > input').attr('checked', false);