You'll get the Send to accountant option when QuickBooks Self-Employed (QBSE) isn't linked to your TurboTax account.
I know that you're already using the same username. However, I still suggest contacting our QBSE Care Team. They have the tool to check and verify your login credentials and proceed with the steps to send your tax info.
Here's how to get in touch with them:
Select Assistant from the top bar.
Enter "Talk to human" until you see "I still need a human".