

Head phone jack. My 8a sadly has none. Not sure any recent Pixels do. I use combination of some HP OTC hearing aids and a Senhouser headset, both blue tooth.
Files transfer. I mosly use Nextcloud or just plugin my phone to my computer directly with USB. I have used syncthing and ssh too. Debian should work but I have more experince with Ubuntu and the USB method works fine there.
This is the answer. GrapheneOS still needs the binary blob updates from Google or probably more correctly Googles suppliers.