I think I agree that this was 100% bad AI generated.

The 100TB Build (~$2,500) is full of errors. The math doesn't add up as presented, the HDD prices are for used drives, and it confuses RAIDZ1 and mirroring together as "five drives as two mirrored pairs + spare = ~80TB usable."

Very first picture even looks like AI

You don't need nearly that much. 26TB factory recertified Exos drives are $360 a piece on Amazon and a 4-bay UGREEN NAS is under $500, so you can do 100TB for under $2000.

More compute, redundancy etc. of course adds cost but even with RAID1, brand new WD Red drives and a PC build, you should be able to do under $6000.

I spent $2550 on a TrueNAS setup with 3x22TB drives, so 40 TB usable after setting up ZFS. The case can hold 8 drives so I could go up to 120TB usable for an additional $2000 at $400/drive. Building big storage servers is actually much cheaper than you think nowadays.

You don't need a lot of RAM to run TruNAS. 16gb should be sufficient unless you are planning lots of VMs.