Hi sb_koeln
I have never heard of anyone doing what you are trying to do. In the professional video industry, there have been countless network attached shared storage systems for decades - from companies like AVID Nexis, Studio Network Solutions, Quantum, Facilis, Editshare, GB Labs, Dynamic Drive Pool, OWC Jellyfish, not to mention QNAP and Synology. NO ONE allows you to just pop out drives, like a cheap drive dock, and move them from system to system. None of these systems are drive docks. And you are talking about need 50 TB per hard drive - drives this size have never existed until about 2 years ago - and they only come from companies like Solidigm and Phison Pascari, and they are INCREDIBLY EXPENSIVE. A single Solidigm 60 TB U.2 NVMe drive is about $6500 for ONE drive. So the bottom line here - is, that you are not going to get what you want - from any manufacturer.
Bob Zelin