I kind of hate opaque cloud solutions like this, because their storage usage is inscrutable and their interfaces are basically never optimized to help you clear things out. Whether that’s intentional and malicious or just not a priority, I don’t really care, I just want to be in control of the stuff I’m using.
I have a very similar issue with iMessage in iCloud, and unlike photos, there’s no web interface. You have to interact with it on your device. Thankfully I have a Mac so I can load up the chat database from there and see what’s using the space, but cleaning it up has been a nightmare: I have a script to find the big attachments, but if I delete them then some agent that manages the database goes into a loop for like five minutes per deletion. Then the change gets synced to iCloud (at least, I assume). So unless I fully reverse what the deletion process does and whether it is possible to do a batch operation I’m basically at the mercy of the front end they provide to clean things up, which as I mentioned earlier is absolutely not designed to make it easy to do this.
I have a very similar issue with iMessage in iCloud, and unlike photos, there’s no web interface. You have to interact with it on your device. Thankfully I have a Mac so I can load up the chat database from there and see what’s using the space, but cleaning it up has been a nightmare: I have a script to find the big attachments, but if I delete them then some agent that manages the database goes into a loop for like five minutes per deletion. Then the change gets synced to iCloud (at least, I assume). So unless I fully reverse what the deletion process does and whether it is possible to do a batch operation I’m basically at the mercy of the front end they provide to clean things up, which as I mentioned earlier is absolutely not designed to make it easy to do this.