There should be a way to choose which of all the available configured shipping methods should be selected by default.
It could be either:
- from the admin side where the shipping methods are configured
- using the Snipcart API
- using a tag on the
<shipping-rates-list>
or on the<shipping-rates-list-item>
maybe something like:defaultChecked={rate.slug == "whateverShippingSlug"}