It's been a while since there was any word of an save editor. Now there are a few (paid versions) that can edit a savefile and re-sign saves for your PS4.
1 - Save Wizard
2 - Cyber Gadget's official Save Editor
3 - Xploder PS4 Cheat System
After some research on all 3 of them, the save wizard seems the best option. Cyber gadget's is only for JP and Xploder is just a rip off that copy everything save wizard does.
I did buy the Save wizard, and it works pretty fine, everything works what they claim the tool can do. Only downside is that all magic happends serverside, so the program uploads your save applies edit and downloads it back. And there were times that proces took ages (according to some people). But Save wizard said they fixed it. But when I wanted to edited my Final Fantasy XV savegame it took a while for the upload proces. In the end my save edit was succesfull and it actually worked when I tested it.
After save editing I tested out the resigning feature and that also works flawless, some trophys even popped right away while others had to be triggerd by completing a mission or collecting 1 collectable. We all know the region codes for games is a thing, but be aware that sometimes disc games are different from downloaded games so saves can be different eventhough it's the same game from the same region.
keep in mind every firmware update might render the save editor useless...
So if you wanna save edit and don't mind to spend some money I reccommand the save wizard