Can I use the macOS Photos app to mirror photos from an iPhone? I don't use Photos for anything other than showing photos taken on my iPhone, so I'd like the library on the macOS side to perfectly mirror what's shown on my device.

Right now, photos sync from iPhone to the Photos app, and the My Photo Stream view seems to remain current. But if I delete a photo from my phone, it still remains in the library on the Mac side. I'd really like for it to be gone, without having to delete it twice.

Is this possible, without using iCloud?
No, iCloud Photo Library is Apple’s tool for doing what you want to do. They don’t provide another way that doesn’t use iCloud.