Tested on EmEditor v23.0.5 with all default settings in Windows 11 64-bit.
In an empty cell, entering ABCD and then pressing ESC results in retaining a single character A, instead of clearing the cell (v22.5.2 or Excel method).
If the cell initially contains ABCD, entering EFGH, and then pressing ESC, leaves a single character E, instead of retaining ABCD (v22.5.2 or Excel method).
Not sure if there have been changes in the input method in v23.0 or if it’s a problem.