Do you have an old computer that you can use as a server? If not, you could look for one used. Then get an 8TB disk and maybe a second one for backup if you want to store anything you can’t redownload.
You can use any computer you want. It is usually enough with something like a raspberry pi (A raspberry pi can be pretty expensive, so you should look for an alternative). Then just connect some external drives (or internal based on the computer).