Disk/Storage Confusion

I just got back my work iMac that was fixed internally by my company and I am confused as to what happened to my storage.

The original problem was that the computer got stuck in a reboot loop and would error out every time you tried to do a clean OS install on it. Eventually it was decided there was a hardware issue and 4 months later I finally get it back today and am told they had to replace the logic board. Cool. It starts up, it has been reverted back to Monterey, and everything seems fine until I go and check the storage before restoring my back ups and notice I am down to 128 GB instead of the 2TB I previously had.

I work with design and video files, are they kidding? But I notice in Disk Utility that there is a second storage device and it appears to be my 2TB unmounted.

My questions are: What did they do? Can I remount the 2TB and use that as my start up disk? Did they separate it out because it was corrupted and if I do try and remount it, will it restart the original issue? Is there any way to get some of my storage back?

Their first email response to me questioning this boiled down to they do not see the issue, the computer "works," and before I push it, get my manager involved, and am stuck on an old laptop (that at least has 256GB ;__;) for another 4 months, I was hoping there might be a solution I could try myself.

Any help will be greatly appreciated.

Thank you!