If you do not re-sign the save (i.e., just copy a random file from the internet), the PS4 will recognize it as corrupted data and refuse to load it.
If you don’t want to edit yourself:
Borderlands: The Pre-Sequel (2014) remains a popular title within the looter-shooter genre, renowned for its complex skill trees and weapon generation systems. On the PlayStation 4 (PS4) platform, a subset of the player community seeks to modify save files to acquire “god weapons,” infinite currency, or modified character levels. This paper explores the technical methods required to mod saves on the PS4, the pivotal role of Save Wizard software, the security architecture of the console, and the ethical ramifications of injecting modified data into the game ecosystem. Borderlands Pre Sequel Modded Save Ps4