Is it possible to edit a published Unreal game in the editor?

Hi,
There’s a game I purchased on Steam several years back that was made in Unreal called Himiko. It’s since been pulled off the steam store due to Valve ending their business relationship (essentially banning the developer)
It’s very obviously the person’s first game and has a lot of issues, but I believe there is a lot of potential there, so I wanted to try and make a few changes to it for my own sake (not for release, just to see what I could do with it)
I’ve tried changing the .pak file to .zip and extracting it, but it says there’s nothing in it. I can get to all the major assets, but no blueprints or levels or anything, so to make those changes I’d have to first remake the whole thing, which is rather too much effort for something that would basically just be putting my mind at rest.

The way you want to do it, no.
If you create your own project file you can add a patch system to update your own published games.

Fair enough. I’ll look into that for the future then.