The PS5 version of Subnautica just released! It's a seperate download not a ps4 version patch. Make sure you purchase the free upgrade from store [No Spoilers] : r/subnautica
Buy Subnautica: Below Zero from the Humble Store and save 58%
Subnautica PS4 & PS5
Play at Home 2021 update: 10 free games to download this Spring – PlayStation.Blog