First thing, did you look for the RenPy folder that gets created on your machine? Sorry if that's too basic a question, but some people aren't aware it's there. Even if you deleted your game file and the saves/persistent there, your saves and persistent will also be in that RenPy folder. If you already know this, looked, and didn't find anything, well....
I've played through part 5, but if you like, I can provide a save file and a persistent file, and then you can start a new game, but be able to skip through previous content pretty quickly because of the persistent file. I play on a PC.
One caveat, I've named my character "Wyatt", which will become awkward at the end of Ch5. But, since you'd likely be doing a "from the beginning" run and skipping, that shouldn't be a problem for you to change. I've also been using the LightmanP multimod. I think you could probably switch over to Sancho and use his "save tool" to make things work, but may not have to if you're starting a new game. Not sure how that impacts skipping since it wasn't the mod used in the persistent file.
Let me know if you want me to drop the files here, or if you get a better offer. You could also do a search of the thread because I do think there are at least a few "through Ch4" save files already here, hopefully with the persistent included.