In 2022, I lived (and worked remotely) in Maryland for two months, then moved permanently to Vermont (where my employer is located) for the remainder of the year. Unfortunately, my employer withheld taxes as if I was splitting time 50/50 between the two states, and split my taxable state income down the middle on my W2. They refused to provide a corrected W2. I believe I've therefore significantly overpaid my state taxes in MD and underpaid in VT.
Can you provide any guidance on how to best file state taxes in MD and VT given the circumstances?
If your employer won't provided a corrected W-2, enter your W-2 as issued. You will file a Part-Year Resident return for both Maryland and Vermont.
If you report more income to Maryland than you actually earned while a resident there (because of an incorrect W-2), Vermont will give you a credit for tax paid to Maryland, so you are not double-taxed on the income, whether your W-2 reports it correctly or not.
Here's more info on How to File a Part Year Resident Return.