FYI: I installed the game manually from scratch after backing up and then removing my steam version of FO4 and it works fine. I've already manually added most of my favorite FO4 mods that are applicable too.
I was getting a lot of CTD's so I added Buffout4, which I'd never even heard of, and it helped a great deal.
I still get some random CTD's. Sometimes it seems vram isn't released when I load into a new location and my 40 series Nvidia GPU has never been 100% stable in any game.
If you can't get the game working, your making some mistake and that's ok. That's how humans learn, by failing until they don't.
I do have a lot of experience with FO4 and mods for it and I learned it all through reading other peoples posts and trial and error.
Just remember to back shite up before you bugger it up so you can easily go back to the beginning while your learning how to make the game work the way you want it to.