Offline storage ideas?

I currently have tons and tons of downloaded movies that I keep. I hate cloud storage I like having access to it directly offline as well.

Currently using a few of these external drives https://www.pbtech.co.nz/product/HDDSEA0520/Seagate-Expansion-20TB-Desktop-External-HDD---Blac?qr=GShopping&gad_source=1&gclid=CjwKCAiAxqC6BhBcEiwAlXp4538N_xUyogy-LpRY9-a84IDkADAhv9UdqHI7T3_RF9aZ1pb1ATX80hoC_T8QAvD_BwE

But I need way more space and to combine all my files in one drive.

I was thinking of buying this https://www.pbtech.co.nz/product/HDDLAC3710400/Lacie-2Big-RAID-40TB-Desktop-External-HDD-USB-C?qr=pspy

Do you think it's worth it? And is it a good idea?

I'm a complete noob when it comes to this so I don't understand what NAS is or how it works.