Tiny particles have extraordinary thermal conductivity due to their unusual characteristics, making them crucial in materials science, nanotechnology, heat exchangers, and electronics. When there is the inclusion of thermal radiation, a heat source, and a convective boundary, magnetohydrodynamic (MHD) micropolar, tangent hyperbolic flow for water-based Al2O3 nanofluid over a stretching sheet, this work intends to investigate the significance of a nanoparticle's radius. The mathematically described ordinary differential system is created by transforming a set of partial differential equations via similarity transformations. The bvp4c approach is used to solve the problem numerically (MATLAB built-in function). In this comprehensive study, the main objective is to improve heat transformation under the impact of various parameters. The velocity profiles, temperature distribution, micro-rotation distribution, and the local skin friction factor, along with the rate of heat transfer, have been displayed with several physical parameters. It is observed that the variation in velocity and the temperature profiles is the cause of increasing the size of the nanoparticles and the involving parameters that caused an increase in the rate of heat transfer. Graphs and tables have then been used to demonstrate the consequences of these physical parameters. The enhancement in the radius of nanoparticles causes a decrease in the skin friction factor, thermal layer, and micro-rotation. As the Biot number increased, the thermal layer became thicker. The impact of influential parameters on physical quantities is illustrated using three-dimensional graphs.