calculus - How can I solve this crazy limit? $lim _{xrightarrow0}frac{1-cosleft(frac{1-cos x cos 2x}{x^2}-frac {5}{2}right)cos2x}{x^2} $

Firstly, I think this can be done with equivalent infinitesimal, but it seems so much complicated. I'm not very brave to do L'Hospital's rule on this question. And I don't think trig formulas can simplify this..

$$\lim _{x\rightarrow0}\frac{1-\cos\left(\frac{1-\cos x \cos 2x}{x^2}-\frac {5}{2}\right)\cos2x}{x^2} $$