I don’t know how long you’ve been 3d printing, I don’t have an ender 3, but I have the 5 which is pretty similar. And I haven’t printed the Sanctuary Hills yet, but I have printed a bunch of the Vault stuff. I played with the settings a little, but I think I kept it pretty much on default settings on Cura with little adjustments to the speed and infill settings. Also, where the walls connect to the wall connectors… I don’t remember what they’re actually called… The tongue on the walls were too thick to fit in the grooves of the connectors so I had to print the walls thinner so they would fit. This took a bit of tinkering to get right. Other than that though I didn’t really have to do much.
But the important question is how long have you been 3d printing in general and have you gotten your printer dialed in to an acceptable level? Especially on the ender 3, where the bed moves back and fourth, printing a tall/thin model is going to pose different problems than printing a fat/thick model.
If you haven’t had it for long, you might want to check out some videos and websites to get it dialed in. The ender series printers are great for the price, but their setback is that they need some significant tinkering at times. Some people print great out of the box and some can only get spaghetti. I’m not smart enough to talk you through all the troubleshooting processes, but if you haven’t, I’d suggest checking out the ender3 subreddit and the millions of videos on youtube about the subject. I’ve learned a bit from Teaching tech, 3d printed tabletop, and… Others that I stumble on, but can’t quite remember what they’re called.