We made an article about it a while back.

GrapheneOS Discussion Forum

Response to dishonest attacks on the GrapheneOS project by Robert Braxman - GrapheneOS Discussion Forum

GrapheneOS discussion forum

In short, the guy is a hack who makes content about topics either scaremongering people or peddling misinformation without any oversight. His content disrupts numerous open source projects' communication channels because they ask questions about meaningless, made up things they learn from his videos. He said GrapheneOS is dying and that Google stopped open sourcing AOSP (both untrue). He creates a lot of products which as you can see, are terrible both security and privacy wise.