I strongly believe that your Sarah unknown, who many believe was Sararh Winters, is Sarah Randel, daughter of Joseph Randel. Her birth is recorded at Bush River MM, Union County, SC, born 20 Dec 1763 probably born Western Branch MM, Southampton County, Virginia (many records there were lost and begin at 1767).
10 Apr 1802 - Franklin County, Georgia - Deed to Joseph Randel - 145 acres from John Nix
John Nix had daughter, Anna Nix b. 1781 married Thomas Roberds b. 1769 - Thomas Roberds had married Hannah Randel in 1790 and died abt 1800 - she was daughter of Joseph Randel. (I have DNA connections)
John Nix had daughter, Rachel Nix b. 1784 married John Roberds Jr (I have DNA connections)
John Nix had son, Joseph Nix b. 1787 married Martha Bishop b. 1785. (I have DNA connections)
John Nix had son, William Nix b. 1788 married Susannah Stonecypher b. 1790. (I have DNA connections)
John Nix had son, Jonas Nix b. 1796 married Lucinda Holmes b. 1796. (I have DNA connections)
John Nix had son, John Nix b. 1796 married Elizabeth Isabelle Holmes b. 1798. (I have DNA connections)
John Nix had son Moses Nix b. 1804 married Martha Malinda Harvill b. 1806 (I have DNA connections)
I am not a descendant of NIX surname but I have many NIX DNA connections. I am descendant of Joseph Randel through his daughter, Ann Randel b. 1773 married Joseph Roberds b. 1766.
I believe that Ann Randel's sister, Sarah Randel married John Nix and that she is the mother of their children.