If your equation contains an exponential function or a logarithm function but cannot be brought to the form of equations (1) - (4), you could try to apply a predefined generalization of Lambert W.
See e.g. [Corcino/Corcino/Mezö 2017], [Dubinov/Galidakis 2007], [Galidakis 2005], [Maignan/Scott 2016], [Mezö 2017], [Mezö/Baricz 2017], [Barsan 2018], [Castle 2018].
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[Castle 2018] Castle, P.: Taylor series for generali-zed Lambert W functions. 2018
[Mezö 2017] Mezö, I.: On the structure of the solution set of a generalized Euler-Lambert equa-tion. J. Math. Anal. Appl. 455 (2017) (1) 538-553
[Mezö/Baricz 2017] Mezö, I.; Baricz, A.: On the generalization of the Lambert W function. Transact. Amer. Math. Soc. 369 (2017) (11) 7917–7934 [Mezö/Baricz 2017] Mezö, I.; Baricz, A.: On(On the generalization of the Lambert W function. Transact. Amer. Math. Soc with applications in theoretical physics. 369 (2017) (112015) 7917–7934