iCloud storage and restoring photos

A few months back, most of my older photos randomly disappeared and at the bottom of the app it said that restoring/backing up photos was paused due to storage. I recently went on holiday and obviously want to back these pictures up, so I deleted lots of photos (over 2,000) from my iCloud assuming that it would work. It didn't. Then I upgraded my plan to 200GB, from 50GB, because I was sure that that would work. But it hasn't. I've deleted apps and data, deleted back ups, and it still says 'Restore from iCloud paused. Not enough iCloud storage'. Before, there was a pause button and a progress bar but this has all disappeared. I really don't want to upgrade again and I just want to back up a few hundred pictures and get my old ones back on my phone. So how much storage does restoring pictures and backing up pictures really need? At the moment I have 6,500 pictures (which is excessive I know!) (and I literally only want a few of these backed up) and I was going to delete some of these but if it doesn't even aid in what I want done, I'm hesitant. Does it need more time to register that there's more iCloud storage? Do I need to wait until night? Any advice? Thank you.