Using ifthenelse inside tikzmath

I’m trying to draw a simple plot of certain line I need, and I’ve used a conditional to generalize every case.

My MWE is:

documentclass{article}

usepackage{ifthen}        

usepackage{pgfplots}
pgfplotsset{compat=newest}

pgfplotsset{my style1/.append style={clip = false, axis lines* = middle, axis equal, xtick = empty, ytick = empty}}

usepackage{tikz}
usetikzlibrary{calc, math, fpu} 

begin{document}

ifthenelse{4=3}{hi}{bye}

begin{tikzpicture}
    tikzmath{
        lra = 1;
        lrb = -3;
        dor = 0;
        ifthenelse{lra = 0}{dor = 4/lrb}{dor = 4/lra};
    }   
    begin{axis}[my style1, samples=200]
        addplot [red, domain=-dor:dor] ({x*lra},{x*lrb});
    end{axis}
end{tikzpicture}   

    
end{document}  

But I’m getting the error "Argument of ifthenelse has an extra }". I can’t understand why. Using ifthenelse in normal text, it worked.

Any help would be appreciated.

documentclass{article}

usepackage{tikz}
usetikzlibrary{calc, math, fpu}

begin{document}

tikzmath{
  lra = 1;
  lrb = -3;
  dor = ifthenelse(lra == 0, 4/lrb, 4/(or(lra,1)*lra));
}
showdor

tikzmath{
  lra = 0;
  lrb = -3;
  dor = ifthenelse(lra == 0, 4/lrb, 4/(or(lra,1)*lra));
}
showdor

end{document}

> dor=macro:
->4.0.
l.13 showdor

?
> dor=macro:
->-1.33333.
l.20 showdor