QuickBooks Self-Employed Offer with TurboTax Self-Employed and TurboTax Live Self-Employed: To receive your complimentary subscription to QuickBooks Self-Employed through 5/17/21, you must pay for your 2020 TurboTax Self-Employed or TurboTax Live Self-Employed return by 5/17/21 and sign-in and access your QuickBooks Self-Employed account via mobile app or online at least twice by 7/15/21.

You can subscribe to the QB SE version then get the SE tax program for free ... it works in both directions.

https://quickbooks.intuit.com/self-employed/pricing/#pricing

It's been saying this. I've tried doing that. 

"Your subscription ended on April 30, 2021. We’re no longer offering a free year of QuickBooks Self-Employed with TurboTax, but don’t go just yet.

Yes ... you can subscribe to the QB SE version and then get a free TT filing at the end of the year  instead of the old way of buying the TT program and getting a QB subscription free.... it is just a reverse situation.

Of course you could buy one of the QB download versions that you pay for once and use for several years instead of paying every month for a lesser quality program.  

Then here is a tip ... instead of paying for the TT  Online SE version (most expensive) you can cheap out and use the Deluxe Downloaded version (basic if you don't need a state return) instead.