The core obstacle lies in the drastically different Central Processing Unit (CPU) architectures. The PS3 utilized the infamous Cell Broadband Engine, a complex processor with one general-purpose PowerPC core and six synergistic processing elements (SPEs) that developers had to manually program. In contrast, the PS4 uses a standard x86-64 AMD Jaguar CPU—the same family as most desktop computers. These two processors "speak" different machine languages. A PS3 game executable (EBOOT.BIN) contains PowerPC instructions that the PS4’s x86 CPU cannot natively understand. Repackaging the game assets into a PKG does nothing to solve this deep-seated language barrier. It would be like placing a Blu-ray of a French film into a player that only decodes Japanese audio—the container is correct, but the content is indecipherable.

due to fundamentally different hardware architectures between the two consoles

If your PS4 is jailbroken, you can bypass the native operating system to run an emulator: Linux Installation

: Run the game through the RPCS3 interface within the Linux OS. Note that performance may vary significantly depending on the game's complexity. 2. Official Sony Methods