Since yesterday evening I am a happy owner of a Pixel 6a that got GrapheneOS flashed on right after unboxing and preparation of the phone according to instructions on GOS' site.
I used the CLI method on a Archlinux system with GNOME. I was a bit hesitant because of the following remark on the instructions' page:
On Linux, GNOME has a bug causing compatibility issues with the installation process. It wrongly detects the phone in fastboot mode or fastbootd mode as being an MTP device and claims exclusive control over it. This will block the install process from proceeding. We don't yet have more specific instructions on working around this issue than avoiding GNOME or another desktop environment running the GNOME services such as GVFS. We expect the problem is in GVFS, so stopping all of the services should work, but you'll need to mask them or they'll auto restart.
The installation went just fine though without the need to do any adjustment being done for the GVFS issue described above. If you want me to provide more specific info on my Linux system, please feel free to ask.
I would need to start reading up on documentation and take some time to acquaint myself with GOS . I would greatly appreciate any comments and suggestions and look forward to meeting the GOS' community.
Lastly, I would like to thank the GrapheneOS' developers and everyone involved in the project for all the great work.