PS3 games rely on libsyscalls, SPU threads, and RSX graphics commands. The PS4's Orbis OS (a modified FreeBSD) does not have these libraries. Your PKG would need to include a full translation layer, which is a decade-long software engineering project.
There is no native way to install and play PS3 files directly on a ps3 to ps4 pkg install
Installing PS3 games directly as PKG files on a PS4 is not natively possible PS3 games rely on libsyscalls, SPU threads, and
For those looking to manage PS3 files on actual PS3 hardware, tools like or Irisman allow you to mount and install PKG files from external NTFS or exFAT drives. Install PKG Files over Network - ConsoleMods Wiki PS3 games rely on libsyscalls