Back up photos to iCloud

I currently have several Apple devices and I wanted to back up pictures from one device which I had never done before. However, the images in this one device are not backing up after I did all of the steps of how to back up images to iCloud and instead, it is uploading 30,000 items I have in my iCloud pictures from other devices. Any advice on what I should do? As to how to back up without needing to upload the 30,000 pictures on my iCloud?