Uploads are frustrating

I like Flickr but have had a lot of uploading problems with the iOS apps. While Google Photos and Amazon Photos for iOS quickly find new photos and videos to back up on my phone, the Flickr app seems to take a very long time. I will often open the auto-uploader screen and watch the number of remaining items to be uploaded. It is a vast number which hardly changes. Am I doing something wrong?

climb_ice about Flickr, v4.3.0