Macintosh HD - Data

There is no need to erase and reinstall. Read through the thread here and follow the suggestions by Barney:

https://discussions.apple.com/thread/252051761

And to be clear: You should have a Macintosh HD volume and one Macintosh HD - data volume. The first one contains the OS and all system files and the Data volume contains your User folder and all other files/data.

You should only have one; duplicates are usually the result of a reinstall of the OS. You can check them and if they do not contain any data, they can be deleted.