Personally anime uses around 30TB for me. For the best quality (mostly 1080p + bluray) of everything released in the last year (~250 shows / movies), but also including older releases for the same franchise (eg past seasons / related spin offs).
For western media it'll really depend on how much quality you're willing to forgo (4k? hdr? blu-ray rips?) but 20GB for a 1080p season pack (~10 eps) and 5GB for a movie is pretty normal. And a cursory glance at certain sites suggests 250 seasons and 850 movies were released in 2023, so ~15TB seems like a good estimate for a years worth. Releases for asian stuff should be pretty similar in size, except less hdr / bluray options.
Storage wise I just have a raid 1 (zfs) setup with a bunch of 14tb drives (at 8~10usd per TB [1]). I did need to buy a hba doodad to convert a pcie slot to more sata slots though.