The relevant concept in your situation is that of domicile. Your domicile is your main, primary, permanent home. You are a domiciliary resident of the state where your domicile is located. Your domicile does not change unless you abandon it in one state and establish it in another.
You can also be a statutory resident of another state for tax purposes. For example. KY considers you a resident for tax purposes if you are domiciled in another state but maintain a place of abode and spend 183 days or more in KY during the tax year. A person can be a domiciliary resident of one state and a statutory resident of another.
A part-year resident is a person who moves his domicile from one state to another during the tax year. Since you never truly moved to KY (your words), your domicile never changed from FL. Therefore by definition you never became a part-year resident of KY.
So:
2021: Your domicile was in Florida all year, and you spent fewer than 183 days in KY. You were a non-resident of KY.
2022: Your domicile was in Florida all year, and you maintained a place of abode and spent more than 183 days in KY. You were a domiciliary resident of FL and a statutory resident of KY.
2023: Your domicile was in Florida all year, and you maintained a place of abode and spent more than 183 days in KY. You were a domiciliary resident of FL and a statutory resident of KY. (You had no "move-in" date since you never moved your domicile to KY.)
Since you were a non-resident in 2021, you would only be taxed by KY on Kentucky-source income, such as earnings from work carried out in Kentucky or rental income from property located in KY. If you had no KY-source income, then you had no filing obligation in KY for that year.
For 2022 and 2023, you would file a KY tax return as a resident. ALL of your income, regardless of source, would be taxable by KY in those two years. (If Florida had an income tax, your income would also have been fully taxable by FL. Your situation is greatly simplified by the fact that your domiciliary state has no income tax.)
Section 32 of this reference has the KY definition of "resident" for tax purposes:
https://apps.legislature.ky.gov/law/statutes/statute.aspx?id=53496
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
