I recently stumbled a link from across DocumentCloud from Muckrock Foundation that serves as platform for documents for journalistes and document heavy investigatons.
Unfortunately for this purpose they have decided to go for Filecoin in 2022
But maybe partnering would be still possible for additional resilience or simply to have an alternative. So maybe it is worth to contact them and offer help with their mission.
Filecoin still exists?
Unencrypted and unreliable Filecoin for documents? 
As I understand it they serve 2 purposes with that. One is to offer a independent and reliable space for newsrooms where document sources for articlescan be published and the other where newsrooms can run it locally if they need more privcacy for their documents:
But yes, would be a great purpose for Storj storage.
Yes, with about 20000PB of unused storage space. At least sia is using most of its couple of PB and arweave I suppose 100% is used but mad amounts of replication
And how reliable are those estimates? I can just as well put 10EB of “storage” into my storage node 