You will not be able to use Section 1031 for this transaction because that section allows deferral of gain only when property used in a trade or business (or for investment) is exchanged for other property used in a trade or business (or for investment). Section 1031 simply does not apply to property held for personal use.
In this instance, your replacement property was clearly purchased for use as a primary residence and not for investment or business use. There are also time constraints on the identification of the replacement property and the completion of the exchange as well as constraints on how the exchange must be handled with respect to receipt and disbursement of funds.
See https://www.law.cornell.edu/uscode/text/26/1031 and
https://www.irs.gov/pub/irs-news/fs-08-18.pdf
If your move (from property A) was work-related and/or meets other requirements or exceptions, you may be able to exclude some of the gain (a partial exclusion) from that sale (see the note below the link, however).
See Publication 523 (2020), Selling Your Home | Internal Revenue Service (irs.gov)
With respect to renting property A, you were required to take depreciation deductions each year on that property. If you filed returns for 2018 and 2019 without taking depreciation deductions, then you adopted an impermissible method of accounting which can only be rectified by filing Form 3115.
See https://www.irs.gov/publications/p946#en_US_2020_publink1000107386
Professional guidance would be required in this scenario.
