How are you going to fit 20 drives in that case?
Data Hoarder
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
Fractal says the Define 7XL will hold (18) 3.5" drives but it actually holds 20: https://www.youtube.com/watch?v=FAy9N1vX76o&ab_channel=LinusTechTips
I would get a proper server case with a backplane. It'll save so many headaches with cable management, and they distribute power a lot more safely than running many long cables would.
My system has been a lot more stable since I started using a hot swap backplane and server PSU. Before that I would lose a drive every 3-6 months. It's also a lot quieter and the drives run cooler.