Developing dielectric films with high energy density and efficiency under extreme conditions is crucial for the stable operation of advanced devices like electric vehicles and energy storage systems. This work designs a rational linear–nonlinear–linear (LNL) sandwich architecture, with MOF-enhanced PEI insulating layers (EZ) as the outer layers and horizontally aligned P(VDF-HFP)/TNTs composite films (PT) as the middle polarization layer. The multi-site bonding network within the EZ layer, constructed by activating the Zn²⁺ sites on ZIF-8 via the thermal field during imidization to coordinate with the PEI monomer (ODA), significantly enhances the breakdown strength (reaching up to 664.50 kV/mm for the EZ1 composite film) and suppresses leakage current. Meanwhile, the horizontal orientation of TNTs in the PT layer, achieved through an electrospinning process combined with hot-pressing, improves polarization performance while maintaining high breakdown strength. The resulting ~20 μm EZ-PT-EZ LNL film achieves a high Ud of 13.68 J/cm³ (η = 85.5%) at 620 kV/mm and 25 °C, and retains a Ud of 8.51 J/cm³ under harsh 120 °C and 520 kV/mm conditions. The excellent performance originates from the synergistic effects of the widened bandgap of the EZ layer, the inhibition of charge carrier transport by the reverse built-in electric field formed at the L/N interface (opposite to the applied field), and the combined hindering effect of the interlayer interface and horizontally oriented fillers on breakdown path propagation. This work provides an effective strategy for designing high-performance polymer dielectrics through synergistic structural design and band structure engineering.