How to upload photos from iPhone to iCloud Storage without being "managed" by sync?
Solution 1: Manual Uploading/Tracking to Files.app
If you want to stick to iCloud Drive and achieve the this, you'll need to manually upload your photos to iCloud using Photos -&gt; Select -&gt; (Select Photos) -&gt; Share -&gt; Save to Files
In this method you'll have to manually keep track of the photos you've uploaded and the new ones that haven't been uploaded yet.
Solution 2: Google Photos for iOS
Google photos app for iOS brings the same

Free Photo and Video Storage

feature for iOS, which were initially advertised with the Google Pixel.
Note: Google Photos will automatically reduce your photo quality if you use the free plan.
In this method, the app handles the sync history and keeps track of the backup metadata for you, so you won't have to worry about uploading new photos manually.
App Store: Google Photos