Other system data taking 30 GB of my storage?

Hi! So i have a Iphone x. It's pretty old. One day I realised that: "oh, my storage if full" It was, i got only less than a GB left (My phone is 64GB) Half on my storage was being used by system data? What is it? How does it take that much?? It's possible that it's a virus or something but does anyone have any sugestions? Im also using ios 14, the lastest version.