Why do I have 4 unused disks / partitions on my new computer?

I recently got myself a Huawei Matebook and I noticed that I was missing 40 GB of hard drive space, because the C: disk is 80 GB and the D: disk is 380 GB and I only have 460 GB available instead of 500 GB (of these 460gb are still about 20gb because of Windows and Office, etc. Occupied, so that's not what I mean).

Then I looked in the disk management and discovered 4 more disks with a total of about 16GB of storage space. These are not assigned to any file system and are completely empty (and also not visible outside the administration).

My question would be, why are these disks preset and can I possibly resolve them to enlarge my C:?

If I were you, I would ask Huawei support, it doesn't sound normal to me, but I don't use Huawei or laptops in general either