In the hunt for novel materials, we present self-consistent ab initio simulations of the structural stability, electronic profile, and transport properties of f-electron-based RbMO3 (M = Np, Pu) perovskites within the context of density functional theory. The structural stability and thermodynamic concerns are fixed by relaxing the crystal structure and computing the energy of formation, respectively. Furthermore, the decisive physical features of given materials have been outlined using the optimised lattice constant retrieved from structural optimizations. The ground state magnetic phase stability is ascertained by minimizing Birch Murnaghan's equation of state in distinct magnetic phases, upholding the ferromagnetic phase (FM) as the ground state magnetic phase, which is further backed by positive Curie Wiess constant values. To specify the electronic structure, a mix of the two approximations GGA and GGA + mBJ has been executed, both of which assert the half-metallic character, culminating in 100% spin polarisation at the Fermi level. The study of the magnetic moment and Curie temperature of each material has further been assessed in the present study. Apart from half-metallicity, the thermoelectric response of the present materials is quantified by exploring the chemical potential dependency of several transport parameters like Seebeck coefficient, electrical and thermal conductivity, power factor, etc. Moreover, the thermoelectric competence has been tested using a zT calculation, adapting values of 1.01 and 0.987 at 300 K for RbNpO3 and RbPuO3, respectively. The high electronic zT at encompassing temperatures uncovers the significant utility of these materials in both low-and high-temperature thermoelectric device applications. In essence, the comprehensive survey of these alloys could certainly open up their possibilities in spintronics, thermoelectric, and solid-state (RTG) device applications.