In this talk, I will present the results of our recent three-loop calculation for the evolution kernel of QCD twist-2 non-singlet operators with transversity Dirac structure. This result also can be seen as the NNLO (next-to-next-to-leading order) off-forward anomalous dimension matrix. Using light-ray operator representation and corresponding evolution kernels provides an efficient way to exploit symmetries of the problem of scale evolution for non-perturbative partonic distributions. Namely, in this approach, we use underlying symmetry of RG-equation under transformation from the collinear subgroup of the conformal group. This allows us to simplify the three-loop calculation by reducing it to a two-loop calculation of a specific term called the conformal anomaly. I will give an overview of the conformal anomaly method, which relies on considering QCD at a critical point in non-integer dimensions, and will outline some technical parts of our work, including the calculation of Feynman diagrams and solving differential equations for the integral kernels of evolution operators. This talk is based on the paper [2407.12696] in collaboration with Alexander Manashov and Sven-Olaf Moch.