<p>This work investigates thermoelastic wave propagation in a fibre-reinforced plate interacting with non-viscous fluid layers while incorporating exponential temperature-dependent thermal conductivity within generalized thermoelasticity. The novelty lies in the unified treatment of reinforcement anisotropy, fluid–structure interaction, generalized thermal relaxation, and nonlinear thermal conductivity effects. The coupled governing equations are formulated under plane strain conditions and solved analytically using the normal mode method for coupled thermoelasticity (CT), Lord–Shulman (LS), and Green-Lindsay (GL) theories. A Kirchhoff transformation is employed to handle nonlinear exponential conductivity while preserving analytical tractability. Numerical results demonstrate that positive conductivity variation enhances heat diffusion and reduces peak thermal and stress amplitudes by approximately 15–25%, whereas negative conductivity promotes thermal localization and increases oscillatory persistence. Fibre reinforcement suppresses displacement amplitudes by nearly 10–20%, indicating increased effective stiffness and improved attenuation of thermoelastic disturbances. Among the considered theories, the GL model produces the strongest damping due to dual relaxation effects. The combined interaction of reinforcement, nonlinear conductivity, and fluid coupling significantly modifies thermoelastic wave attenuation and stress redistribution. The proposed formulation extends conventional constant-conductivity thermoelastic models by integrating exponential nonlinear conductivity with reinforcement and fluid loading, providing new insight into attenuation control and thermoelastic stability in advanced composite structures.</p>