Well since you must file a 2019 return do NOT use the stimulus program ... you must file a complete return and you must use the MFS filing status ... if you have no refund on the return you cannot enter the DD information if you efile the return. But you could manually enter it if you mail in the return BUT mailed in returns are taking 2 months or more to process so this is not a good option.
If your income is below $50K then the stimulus check will be mailed as soon as the return is processed probably in the next 3 weeks ... entering in DD info will not speed anything up. So just bite the bullet and file a regular return ... use one of the IRS FREE FILE options if your AGI is $69K or less ... https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free
