iCloud Photo Library stopped syncing at 1%

I have an IPhone XS Max 64gb. My photos are 30gb and my “Other system storage” is nearly 30gb and I don’t know how to clean it. I decided to buy iCloud storage and when I backed up my photos it stopped syncing at 1%. I tried literally everything I read on the internet: switching off and on iCloud library, signing in and out from Apple ID, charging my phone to 100% and then backing up, forgetting my network then turning it on. Nothing changed. My videos aren’t loading and I can’t make new photos.