For game done with ue 4.25 you need unreal Editor 4.25.
However to open and edit you need UNCOOKED project files. And game usually has COOKED and then packaged files. So you need source files for that game.
Else there is not easy way to edit packages. There was some tool for extracting models, sounds and animations from unreal 4.xx , but no tool that can extract then place altered assets in.