What’s wrong with my storage?

I’m really annoyed right now. I got a new iPhone 13 last Christmas, so around 3-4 months ago. Very new. I just bought more iCloud storage because I can’t take any photos or videos. It still says my storage is full. I have the bare minimum amount of apps, and I have only kept very important photos and videos. No matter what I do, my storage is always full. What do I do? I know that you can’t upgrade the phone’s storage itself, but is there any way you can sync the iCloud so photos and videos stay on it? I’m not going to spend two grand on another phone.