I would like to help, but I can't tell what you are trying to say. For instance, "upload" what from what to what? Can you include exact steps? iPhoto is an app discontinued 10 years ago--to you mean the Photos app, or something else? How did you "import" what? Help us help you by giving details.
Photos doesn't import exact duplicates. I you're getting duplicates, through the normal import process, then they must be different. Do they have different extensions, like heic and jpg?
So, can you tell us a bit more?
- Are you using iCloud Photos to synchronize your devices? If so
- …Do you have “Optimize Storage” checked in Photos’ Settings
- …Do you see all your iPhone pictures at iCloud.com?
- …Do you have more than 10% free storage on your iCloud account?
- What is your storage on this Mac? At Settings>General>iPhone Storage, my phone says 50.5 GB of 128 GB used. What does yours say? Do you have more than 10% free storage on your Mac?