When my friend was telling me about GrapheneOS I was thinking back to the old days of android custom roms, all the bugs and bullshit, the time I couldn't dial out to 911 because my custom ROM crashes when I did, or other issues. So I gave it a pass.
However he's been on it now for months and every time he shows me something on it I get a little more jealous. Everything seems to be working fine, including e.g. bank apps, and he has interesting features like some kind of app zoning thing limiting permissions on a zone to zone basis.
The only problem is it's only available on massive phones without headphone jacks and SD card slots, so I'm sticking with Xperia for now.