@film_girl something that I think isn’t mentioned enough is how restrictive macOS is about where things can go. AppStore apps have to be on the main drive. iPhone backups HAVE to be on the main drive. Messages (including their media) HAVE to be on the main drive. I’ve tried a few things with symbolic links and I just cannot get the data to budge. If you have even a 64Gb iPhone, you cannot do an encrypted backup to wipe and restore or anything like that. It would be fine to have a small primary storage device if you could ensure everything happens on an external SSD, but you can’t.