The most reliable way for this conversion would be to use Lotus 1-2-3 spreadsheet editing software to save .123 spreadsheet file to a .wk4 file (Lotus 1-2-3 version 4). Lotus 1-2-3 is legacy software that was available for MS-DOS, Windows and Mac OS Classic.
But even some modern programs like Libre Office Calc supposedly support both of these file types and should allow users to perform this conversion.