Shipping and split payment

Even after vendors added the shipping rules from there settings and apply the weight for shipping, We can only see the delivery time notice of the product page. prices don’t get increases at the checkout page. I already activate the store shipping for every market shipping options from the woocommerce settings. But still getting same results.

Can’t we check the paypal split payment options from paypal sandboxes? Because I’m getting an error when try to purchase a product using paypal.
Also I can’t see the COD option for vendors. Is it the cash payment method?

Do we have a method to add the shipping updates from the vendor dashboard to their products after a purchase?