\[ \left (y'(x)^2+1\right ) \sin ^2\left (y(x)-x y'(x)\right )-1=0 \] ✓ Mathematica : cpu = 0.0714154 (sec), leaf count = 59
DSolve[-1 + Sin[y[x] - x*Derivative[1][y][x]]^2*(1 + Derivative[1][y][x]^2) == 0,y[x],x]
\[\left \{\left \{y(x)\to c_1 x-\frac {1}{2} \arccos \left (\frac {-1+c_1{}^2}{1+c_1{}^2}\right )\right \},\left \{y(x)\to \frac {1}{2} \arccos \left (\frac {-1+c_1{}^2}{1+c_1{}^2}\right )+c_1 x\right \}\right \}\] ✓ Maple : cpu = 0.271 (sec), leaf count = 139
dsolve((diff(y(x),x)^2+1)*sin(x*diff(y(x),x)-y(x))^2-1=0,y(x))
\[y \left (x \right ) = -x \sqrt {\frac {1}{x}}\, \sqrt {1-x}-\arcsin \left (\frac {1}{\sqrt {\frac {1}{x}}}\right )\]