Two Macintosh HD Data disks, one is taking up so much storage. Can I delete it?

So recently my storage has been decreasing and when I factory reset my MBP 2019, I saw that there's two Macintosh HD Data disks.

The first one looks like this:

The second one:

My Macintosh HD Disk:

MY QUESTION: I need my storage back, can I delete one of them? If so, how do I proceed?

Some background info: I recently factory reset it and during the process of reinstalling Catalina, it froze and so I restarted the laptop. It took me to Internet Recovery and when I went to reinstall MacOS, it was Mojave that I reinstalled instead of Catalina. So currently, the MBP is running on Mojave.

Thanks!