To be clear, I'm on the fence on this. I'm curious about GrapheneOS. It sounds like a cool project, and I've heard that a lot of people like it. Like @QnA says, the brand and the tech are different strictly speaking. The question is whether that is true in practice. Here are the video links:
https://youtu.be/4To-F6W1NT0
https://youtu.be/Dx7CZ-2Bajg