Is there a plugin for changing shipping cost in checkout?

How to change shipping cost when during the checkout?

You would need a customised Shipping Plugin or a "Complete Order Plugin".
Or maybe there is another Plugin that does something like that ?
Otherwise you can edit the stored values in Admin after the order has been created

so I've done this in cshtml and js edits along with an extension controller method, let me see how long it takes me to roll it into a plugin