Hi there.
You need to create a second scenairo for watching new Discord members. You can’t know when they accept the invitation and actually become a new member in advance. So creating it in one scenario and triggering it with Shopify’s Watch Orders doesn’t really make sense to me.
A better approach would be to use Discord’s Watch Guild Members trigger module. Then you can assign the role to the newly created user.
In the first scenario, you can use Shopify’s Watch Order trigger to store the product that the customer bought along with for example their email into the datastore to use later in the second scenario.
Then, in the second scenario, you can add the search records datastore module to get the information about the purchased product and then you can use router and filters to assign the correct role.
Cheers