The proposed study investigates the characteristics of Stefan blowing and activation energy on MHD Casson Diamond-[Formula: see text][Formula: see text]based trihybrid nanofluid over a sheet with LTNECs (local thermal non-equilibrium conditions) and permeable medium. The significance of Marangoni convection as well as heat generation are considered. In order to examine the properties of heat transmission in the absence of local thermal equilibrium conditions, this paper makes use of a simple mathematical model. Local thermal non-equilibrium situations typically result in two discrete and crucial temperature gradients in both the liquid and solid phases. In systems where material qualities and heat transfer efficiency are crucial, the utilization of Xue model and Yamada-Ota model and to assess the thermal conductivity of the nanofluid adds a comparison dimension and enables optimized design. The controlling partial differential equations are reduced to non-linear ordinary differential equations using an appropriate similarity transformation. The Bvp4c technique is used to resolve the resulting equations numerically. Applications in modern thermal management systems, especially those requiring precise heat transfer control (e.g., electronic cooling, medicinal devices, energy systems), will benefit greatly from this work. The model is especially applicable to processes where chemical reactions and internal heat sources are important, like in catalytic reactors and combustion systems, because it takes into account activation energy and heat generating effects. The findings indicate that when the value of the interphase heat transmission factor increases, the solid phase's temperature profile and liquid phase heat transfer rate drop.