Switch with many string cases won't compile in code generation

I have a function .m to be called in a simulink model and generate C code with Simulink coder.

In this function I take an array, that's actually a string converted to uint8, and do a switch with LOTS OF cases.

function out = fcn(stringIn)
%#codegen
[index]=findFirstZero_fcn(stringIn); %find the first zero in the string
localString = char(stringIn(1:index));
if index > 0
    switch localString
        case 'string_firstLength'
           out = something;
        case 'string_secondLength'
           out = something_else;
        %...
        %   140  MORE CASES !!!!! %
        %...
        case 'string_140thLength'
            out = some_other_thing;
        otherwise
            out = some_different_thing;
    end
    
    
end

Strings in the cases are not all the same length.

Running the simulation is perfectly working. When I generate code of the model and compile it, I get a stack error. In fact the generated code turns in an insanely nested sequence of if-else and do-while, that looks not compilable.

The problem is not solved either if I reduce the switch to if-elseif-else or to a series of

if strcmp(localString, 'string_firstLength')
    %set output
return
end

if strcmp(localString, 'string_secondLength')
    %set output
return
end

%etc etc
    

In this case the generated C code is still too nested :

if strcmp(localString, 'string_firstLength')
{
   out = something;
} else {
          if strcmp(localString, 'string_firstLength')
          { 
             out = something_else;
          } else { 
                     if ......
             }
         }
    }
}

The situation does not change either selecting or unchecking the Code Generation configuration option "Reduce if-elseif-else to switch-case".

Any suggestion? Thanks.