If you're changing the orientation, that's part of your problem. The files are all in the orientation I print them.
Default slicer profiles are also bad, they're pretty much all tuned around printing a "benchy" as fast as possible now, and they fail on anything taller than that. You'll have a better time if you slow it down. When in doubt, go slower and/or use support.
I would love for these to just include slicer settings. Unfortunately, they're not formatted in a way that is shareable. I can't just give you a slicer profile, I would need to screencap hundreds of settings (and those settings might still be wrong for -your- printer). It's not that creators don't want to share settings, its that handing them out is not a feature of the program.
There are reddits and youtube videos that DO go down the list and explain all of them one at a time, and the headbases will print with similar settings to the cosplay masks/helmets.
If you actually want help, you need to contact me. I'm not going to do a long comment thread here.