Dark matter sterile neutrinos radiatively decaying in the Milky Way, which can be tested with searches for almost monochromatic photons in the X-ray cosmic spectrum. We analyse the data of the SRG/ART-XC telescope operated for two years in the all-sky survey mode. With no significant hints in the Galactic diffuse X-ray spectrum we explore models with sterile neutrino masses in the 12-40 keV range and exclude corresponding regions of sterile-active neutrino mixing. We also discuss the limits that can be obtained in the framework of the correlation analysis and data from SRG mission.