When a guest user outputs a file in Experience Cloud, the error message shows, "You don't have access to the template file. Access to the template file requires permission to read the OFC_Template record.".
For guest users, the organization's share settings are set to private for all objects. Access permissions to the OFC_Template object for guest users require the sharing rule. See the Salesforce help below for more information.
Best Practices and Considerations When Configuring the Guest User Profile
Create Guest User Sharing Rules
Test Guest User Access in Your Experience Cloud Site
When a guest user saves a file in Experience Cloud, the error message "List has no rows for assignment to SObject" appears, and the file cannot be saved to Salesforce.
It's not supported to save files to Salesforce by guest users. Guest users can only download files.