Let's find the inflection points, we'll need to solve the equation for this
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(the second derivative equals zero),
the roots of this equation will be the inflection points for the specified function graph:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
the second derivative$$2 \sqrt{x} \left(\tanh^{2}{\left(x \right)} - 1\right) \tanh{\left(x \right)} - \frac{\tanh^{2}{\left(x \right)} - 1}{\sqrt{x}} - \frac{\tanh{\left(x \right)}}{4 x^{\frac{3}{2}}} = 0$$
Solve this equationSolutions are not found,
maybe, the function has no inflections