Congrats on retirement planning.
Since the primary home is located in New York, you would need to report home sale gain (with possible section 121 gain exclusion) to:
NY resident tax return, if to be sold in 2024 (taxed as a NY resident) or;
NY nonresident tax return (taxed by prorating tax calculated as if a full year resident), if to be sold in 2025 while you are a South Carolina resident.
NY conforms with Federal treatment of home sale gain exclusion, i.e. If the house was the seller's primary residence for at least two years within the last five years, they qualify for a capital gains exclusion of $250,000 for an individual and $500,000 for a married couple.
If you are eligible for the home sale gain exclusion, and your gain is more than $500K, the excess is subject to both Federal and NY taxes.
Hope the above helps. Thanks for posting the question.
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