I open Graph view not really often, but recently I did and saw just blank page. After some tinkering with settings, updating plugins an so on I found out that if I split graph view, new tab will show graph, but only edges are visible. I can interact with vertices/nodes but they are invisible.
Thus far, I always deleted all contents of .config/obsidian to restore the graph. That to me does not appear to do much harm, but next time, I will try whether indeed just deleting ~/.config/obsidian/GPUCache helps. Indeed, the graph view appears to break now and then on Linux.
What you now did was deleting that cache for the Chromium browser application, not for Obsidian. For a “snap” installation, the corresponding configuration data is stored under a folder of the application under the “~/snap” directory. So look for a folder Obsidian there.
Interesting. My first move was to search whole home directory for GPUCache folder via fzf and chromium is the only one present on my system. Also, it appears that there is no obsidian folder in my ~/.config.
It depends on how Obsidian is installed. I use the appimage. This creates the config folder under ~/.config/obsidian, a standard location also for applications installed using the traditional APT system of Debian and thus also Ubuntu. If your Obsidian is installed as a snap, its config folder will live under ~/snap. For flatpak installs, it will be under ~/.var/app.