I've seen many people have insane setups to download things automatically and NAS' with tens of terabytes of capacity, which i don't understand at all.
I have a 1 tb drive from 2013 of which I'm using ~850GB and most of the space is used by series i have already watched and haven't bothered to delete.
What are you storing to need so much space and how are you finding so much good content that you actually want to save?
Usually what happens is a simple set up of a laptop with Kodi and a 1tb external drive turn into a hobby and you end up with huge NAS set ups with docker stacks. It's so much less about about the actual content and more about the hobby. At least for me it's become that.