You're getting beyond my level of expertise.
Form IT-203-F covers restricted stock. I'm not sure that's exactly the same thing as RSUs, but it sounds like it is. The complication is that, even though the RSUs didn't vest until 2022, they were awarded based on your work for the company in an earlier period, before 2022. If you worked in New York, telecommuted to a New York location, or lived in New York at any time during the period for which the RSUs were awarded, then part of the income is New York income and you probably do have to fill out Form IT-203-F and pay New York tax on the New York portion of the income.
On the other hand, if you never worked in New York, worked remotely for a New York location, or lived in New York, then it remains in the category of a big mistake by the employer. In that case, if you fill out Form IT-203-F (Schedule B would seem to be applicable), what they call the "New York workday fraction" is going to be zero, like on the IT-203-B, making none of the RSU income subject to New York tax. Again, your explanatory letter should clearly state that you did not live in New York or work in New York, either physically or remotely, at any time. If you did live in New York at any time it gets more complicated.
This is a pretty obscure area of New York tax law. If no one who is more knowledgeable about it posts a response here, you might want to try to find a tax professional in New York who can help you. If you are near the New York border you can probably find a local tax professional in Pennsylvania who is familiar with New York taxes and has the necessary expertise.
