February 26, 2021 Bloomberg reports that Sony has been working toward the possibility of people being able to install additional storage into their own PlayStation 5 consoles as early as this summer. Do to the design architecture of the PlayStation 5, the console currently requires very fast read/write access of the M.2 SSD storage format. This makes it impossible to use standard, older external drive options for increasing drive space.
When implemented, upgrading storage will involve manually opening up the PlayStation 5 cover and installing an additional SSD into the expansion slot. The ease of this process can only be speculated on at this point. Hopefully it will be something that is simple enough for the average user to do as storage for games will quickly become an issue in the days of modern graphics requirements.