New York uses the concept of domicile in relation to whether or not you are considered a tax resident of the state. From the New York State FAQ page you linked to:
How do I know if I am a resident of New York State for income tax purposes?
Generally, you are considered a New York State resident for income tax purposes if you are domiciled in the state. For most people this is straightforward: the primary residence where you live is both your state of domicile and the state in which you are a resident for tax purposes. However, you can still be considered a resident of New York State for income tax purposes even if you are not domiciled in the state. (See below, “Can I be a resident of New York State if my domicile is elsewhere?”)
Can I be a resident of New York State if my domicile is elsewhere?
You may be subject to tax as a resident even if your domicile is not New York.
You are a New York State resident if your domicile is New York State OR:
- you maintain a permanent place of abode in New York State for substantially all of the taxable year; and
- you spend 184 days or more in New York State during the taxable year. Any part of a day is a day for this purpose, and you do not need to be present at the permanent place of abode for the day to count as a day in New York.
As you can see, the "184 days" requirement does not apply if your domicile is in New York.
From what I can tell from your question, it sounds to me like your domicile is now in New York State. If I'm reading this correctly, that makes you a New York State resident, regardless of the number of days you have been there.
As for Massachusetts, their page states:
Full-year residents
If you're a full-year resident with an annual Massachusetts gross income of more than $8,000, you must file a Massachusetts tax return.
You are a full-year resident if:
- Your home is in Massachusetts for the entire tax year; or
- Your home is not in Massachusetts for the entire tax year but you:
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- Maintain a home in Massachusetts; and
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- Spend a total of more than 183 days of the tax year in Massachusetts, including days spent partially in Massachusetts.
Full-year residents use Form 1: Massachusetts Resident Income Tax Return.
Part-year residents
If you're a part-year resident with an annual Massachusetts gross income of more than $8,000, you must file a Massachusetts tax return.
You are an individual part-year resident if you:
- Move to Massachusetts during the tax year and become a resident; or
- Move out of Massachusetts during the tax year and end your status as a resident.
Part-year residents use Form 1-NR/PY: Massachusetts Nonresident/Part-Year Tax Return.
The "183 days" requirement does not seem to apply to you, either, because you no longer "maintain a home in Massachusetts.” Instead, you seem to be a part-time resident, because you did "move out of Massachusetts during the tax year and end your status as a resident."
