I appreciate input from others with a similar experience - I lived and worked in DC throughout the entirety of 2022, and my employer failed to incorporate the address change I sent at the end of 2021. I obviously owe DC taxes, and need to figure out how best to file with Maryland as a nonresident to get the entirety of what was deducted to me in 2022 refunded. Thanks for any insights!
To get a refund of your MD taxes withheld when you were not a resident and did not work in the state, you will simply file a non resident return reporting no income only taxes withheld.
To easily generate the MD return, in the personal info section of TurboTax, it will ask if you earned money in any other state. Select yes and MD. This will simply tell TurboTax to add a state return. When you start the state return, you will select that you are a non resident then walk through to the income adjustment section. Here you will remove the income leaving only the taxes withheld. You should see your MD refund jump to the full amount you had withheld.
You may want to double check to be sure that your employer updated your address and is withholding for DC for 2023.