This paper explores the effects of an electromagnetic field, variable thermal conductivity, and gravity on the behavior of elastic porous thermo-microstretch media immersed in an inviscid fluid. The study incorporates the Green-Naghdi theory mode III (G-N III) and the three-phase-delay model (3PHL), which considers the coexistence of thermal waves, porous microstretch waves, and phase delay effects. The analytical strategy for deriving ordinary differential equations is normal mode analysis, then using the eliminating method between six ordinary differential equations, and finally using the characteristic equation to obtain the precise formulas for the physical quantities covered with an infinite fluid of G-N III theory to those of the model 3PHL. Thermal conductivity, the magnetic field, and the gravity have been shown to have a significant impact on all physical quantities.