I don't know that I'd take on tape with your use case. There's a good bit of tech debt involved there.

NAS (either bought or built) + Amazon glacier or Backblaze for cloud archival backup.

The NAS (including drives) will probably cost you $7000-8000 USD for 400ish TB of storage with room to grow

It was easy to give clients access to old data directly if they needed, etc.

I hope you charge for this. It would help to offset your storage costs.

$2000 - 45 Drives HL15 case, motherboard, etc

$2000 - 6x22 TB WD Red (or whatever size you can get after black friday)

$1000 - 5x4 TB SATA SSD of your choosing

132 TB of HDD storage (raw) + 20TB of SSD storage (raw) delivered over SFP or 10GBe

How fast is fast? SSD fast? 7200RPM HDD fast? Whats your use case? You (generally) get to pick two.

• Massive amounts of Storage
• Fast storage
• Reasonable Budget