As @TomD8 said above, Delaware has interesting rules regarding out-of-state telecommuters during the pandemic. If your employer required or "strongly encouraged" you to work from home in 2021, then the income is not attributable to Delaware.
At any point in 2021, your office may have reopened and your employer allowed you to work in Delaware. Even if you chose not to and continued to work remotely in Maryland, your income is taxable by Delaware from the date you had the ability to work in your office.
If you have income taxable by both Delaware and Maryland, do your nonresident Delaware return first. Maryland will then provide a credit for the taxes paid to Delaware.
@edeyrup
