If you open Photos with a brand new library with no pictures in it, and in Preferences you set this library to be your "System Library," you check "Copy items in the Photos Library," and you set "iCloud Photos," and do the same on your phone, then after a couple of days (yes, days--be patient) you will have all the pictures from your phone viewable in Photos on your Mac. There should be no duplicates. But, if you start with a library that already has pictures in it, then there may be duplicates.
If you need to create a new library, then quit Photos and option-click on the Photos icon to get the choice of creating a new library.
If you have photos from your phone stored in folders on your computer, then they will stay there and won't be imported to Photos.
If in Photos Preferences iCloud you check "Optimize Mac Storage" then Photos will keep only lower resolution images on your computer while the full images are stored in iCloud.