You can plug in an SSD up to 8TB with your PS5
(Android Central)

Best answer: Just like the PS4, the PS5 supports external hard drives and SSDs up to 8TB, so that`s the maximum amount of storage you can have in addition to its built-in SSD. It`s unknown whether the same limitations will be in place once Sony expands its internal storage options. Why do I need more storage on my PS5? Every PS5 comes packed with an 825GB internal SSD, and only about 667GB of that is usable for your games. When games can reach 50GB to even 100GB each, that only leaves room for a handful. And if you happen to buy smaller games around 20GB, you`re still looking at a few dozen that you can store at any one time. If you play games frequently, you likely have more games than that. Since it can be a hassle to continually delete and redownload games, you`ll want to pick up some extra storage. Does the PS5 support internal SSDs? Though Sony will be adding expanded internal storage support for the PS5 at some point, it doesn`t currently support it. PS5 storage is a bit co...