... generally, LambertW is not clearly understood.
LambertW is not a function, it is a "function solution"
of which the argument is the solution that you plug in W(x).
Working with Lambert is working in the "domain solution",
something like working in Laplace, Fourier, Hilbert ... domain.
Laplace, Fourier after working in their "transform algebra"
they are inversible. Lambert is: done/bingo.