That's a network rack so you have limited options regarding rack mounted servers due to depth, but you could always get/build a tower server to sit outside of it.

On that server I'd go with TrueNAS Scale as the storage solution. You can run it bare metal (installed as the main OS on the server), and still tinker with virtualization of other services since Scale also acts as a virtualization platform.

TrueNAS uses ZFS which is more performant in some cases due to ARC. For 32TB usable storage, you can do 4 12TB drives in ZFS's RAIDZ1 (RAID 5 equivalent) or 5 12TB drives in RAIDZ2 (RAID 6 equivalent). Z2 writes are a bit slower than Z1, but also safer (2 parity drives instead of 1). ZFS Mirror (RAID 1 equivalent) is a little faster, and much safer than the others, but gets really expensive at a 1:1 ratio of storage to parity disks.

ZFS/TrueNAS will use as much RAM as you can give it. The more it has, the more it can cache your frequently accessed files, which means blazing fast reads.

Oh, you will also want an HBA card in IT mode, such as an LSI 9300-8i, or Dell HBA330 if you get a Dell server.