This column formula should work quite generally. It's independent of column names. However, it assumes the data columns are in a sequence and the column number of the start and end columns must be set (as local variables).
Get name of column with max value:
Local( {start = 2, end = 7, L = Current Data Table()[Row(), start :: end]},
Column( Loc Max( L ) + start - 1 ) << get name
);
And for min:
Local( {start = 2, end = 7, L = Current Data Table()[Row(), start :: end]},
Column( Loc Min( L ) + start - 1 ) << get name
);