I was able to successfully install and play zenless zone zero through steam. I installed the game launcher onto my OS drive but the game itself to a seperate Linux drive. I was able to play and install updates for a long time until yesterday. There was a new update out I tried to install it but it said I didn't have enough space. I have 300gigs available on the drive its installed to so I thought for some reason it's trying to install it to the OS drive. I wasn't sure how to fix that so I figured I'd just uninstall it and reinstall it to my second drive. But now when I go to install it, it says my drive doesnt have enough space. I'm not sure why it would say that when I have 300 gigs available. I also tried re installing the launcher onto the drive that I want to install the game on, but it won't install to a drive that isn't C: not sure what I can do now.
EDIT: I tried every solution suggested below, nothing worked. I eventually gave up and connected an external drive that's NTFS and the game installed to that. Thanks everyone for the suggestions.
EDIT 2: after thinking about this I remembered that when I first installed ZZZ, I didn't have my drive auto-mounting on boot. I guess after making that change the launcher didn't like my drive or something
If you are launching the hoyo launcher through heroic then that will also have to obey Flatpak permissions. Since that is how the containers work.
You could try enabling full filesystem access just to test whether is it Flatpak permissions blocking you.
That still didn't work. The launcher is able to see the drive I want to install to but it's improperly reading the disk size, it says there's 15gigs available when there's 300. I've triple checked that it's the right drive. In fact none of my drives have only 15gigs available. But anyway, I found a solution. I have an external drive that's NTFS and its installing to that.