We are trying to setup a Jira Service Management Portal where customers of our product can submit bugs or feedback on the game we are making.
The end goal would be to have a portal available to anyway where they can create tickets for any of the issue areas they are having.
The problem we run into is that we would like users to submit tickets without creating an account to the portal. Is that possible to begin with?
I have Portal Access set to the following:

The issue I run into is that any users that create an account on the portal or submit a ticket, that user account then shows up in other non-Jira Service Management projects.
What I'd like to do is have them be able to make Jira Service Accounts, which only have access to the portal. But I don't want hundreds of customer accounts showing up in the Assignee / Reporter field in other projects that are not related to the Jira Service Management project.
How do I go about doing this?