Usually it says that if you OWE taxes, and the payment date for that defaults to April 15. Are you sure you're due a refund?
The IRS is sending out Stimulus #3 payments in batches, and will take a few weeks to complete them all. This one comes to you separately (and automatically), not as part of your 2020 tax refund. You can check the status here:
Get My Payment | Internal Revenue Service (irs.gov)
