I noticed you nested the function m within itself to iterate it, but Desmos does actually support recursive definitions, so instead of writing m(m(m(m(...m(z)...)))), you can instead define m0(z) with the same definition as the m(z) you have, and a different function M(z,n)=m0(M(z,n-1)). With the initial condition M(z,0)=m0(z). This will allow for you to change how many times the function m0(z) is iterated without typing it manually.