You're right that QuickBooks Self-Employed doesn't allow you to export GIFI files. There may be a potential workaround available for you depending on what you're trying to accomplish.
I'd recommend reaching out to the QuickBooks Self-Employed team directly by sending them a message using the Chat feature in your app. You can also contact them via email by filling out this form: https://help.quickbooks.intuit.com/en_CA/contact. This team specializes in the Self-Employed version of QuickBooks, and they'll have more insight they can offer you in terms of possible solutions.
Let me know if you learn anything interesting. I'd love updates to make sure you got the support you needed.
Have a great day!