If it has been 21 days since you filed your return you can contact the IRS. Help with doing so has been provided by clicking here.
I am in the same situation I was accepted February 12th and still waiting on my refund.
Do not be alarmed about extended timeframes. This year has brought challenges. The IRS is required to reconcile the tax returns and stimulus payments as well as working on the third stimulus payments due to the American Rescue Plan. With the tax season and the changes taking place all at once, a delay should be expected for full payments. They want to be diligent and are required to follow any protocols they have been issued. They will make any adjustments and additional payments as they complete the process.
At this time the IRS has specifically requested that no amendments should be completed for the new unemployment exclusion. This will take additional processing time but it is much faster than amending. Continue to watch for any updates about that.