Don
It's definitely been increasing though, I think it was around 10GB before I installed anything.
What Is Other Storage Space on PS5?
If you head to the Storage section of the PS5 Settings menu, you'll see a breakdown of the type of files being used by your SSD. They are divided into the following categories: Games and Apps, Media Gallery, Saved Data, and Other. While the first three are fairly self-explanatory, the latter can inexplicably explode in size depending on how you're using the console
Here's what Sony describes Other storage space as:
This storage space is reserved for system data needed for games and apps to work properly. The amount of space reserved depends on how your console is being used.
Not particularly enlightening, then. Based on our experiments thus far, we think that this is related to backwards compatibility, although other system settings do appear to affect it as well. In addition to this, it may be impossible to entirely eliminate Other storage space, because it appears this is where metadata about your games is stored — it almost certainly scales with how much content you have on your console. As part of our PS5 guide, we're going to explain some steps you can take to minimise this number.
Not massively helpful