\[ y'(x)=\frac {\csc (y(x)) \left (\frac {1}{2} x^3 \log (x) \cos (2 y(x))+\frac {1}{2} x^3 \log (x)-\cos (y(x))\right )}{x \log (x)} \] ✓ Mathematica : cpu = 0.43147 (sec), leaf count = 59
\[\left \{\left \{y(x)\to -\sec ^{-1}\left (-\frac {9 c_1+x^3-3 x^3 \log (x)}{9 \log (x)}\right )\right \},\left \{y(x)\to \sec ^{-1}\left (-\frac {9 c_1+x^3-3 x^3 \log (x)}{9 \log (x)}\right )\right \}\right \}\]
✓ Maple : cpu = 0.723 (sec), leaf count = 27
\[ \left \{ y \left ( x \right ) =\arccos \left ( 9\,{\frac {\ln \left ( x \right ) }{3\,{x}^{3}\ln \left ( x \right ) -{x}^{3}+9\,{\it \_C1}}} \right ) \right \} \]