Why is System Data and macOS on MacBook Pro consuming a lot of storage space?

I am running a 2020 MacBook Pro with 256GB of storage, Sequoia 15.4. A couple months ago, I signed up for Apple Beta updates. I think these updates might be eating away lots of storage. My sister and I have the same MacBook with the same amount of storage, and the only difference is that the System Data for hers was far less. We have about the same updates, and the same amount of storage used by non-Mac related things (e.g. Applications, Photos, Messages, etc.). Is there a way to uninstall these Beta Updates?

[Edited by Moderator]