Updated
You can try to add the following code, to change the default payment gateway on checkout page. You will have to define the default desired payment gateway ID, in this code:
add_action( 'template_redirect', 'define_default_payment_gateway' );
function define_default_payment_gateway(){
if( is_checkout() && ! is_wc_endpoint_url() ) {
// HERE define the default payment gateway ID
$default_payment_id = 'stripe';
WC()->session->set( 'chosen_payment_method', $default_payment_id );
}
}
Code goes in function.php file of your active child theme (or active theme). Tested and works.
You will always get Stripe as default now:
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/DuhuO.png)
To get the needed payment gateway ID for Stripe , go in Woocommerce > Settings > Checkout and find it in the "Gateway ID" column as in this screenshot:
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/uGbDD.png)