That is a great success for the GrapheneOS team. Proving they can provide a very secure operating system for everyone.
Quereller
No that is not correct. I actually use both. Island etc enables the work profile. Likely, the work profile uses internally a different, additional user account. But for the device owner there are some differences. Work profile apps you can configure, launch and access directly from the main account. Also there is some limited sharing possible. The notifications are also shared. If you use (multiple) additional user accounts very little is shared. I think the cell phone functionality maybe. Apps are also shared internally but that is not transparent to the user.
I have read that blog entry and some of its references. The evidence provided for this strong claim seems to be very weak. I would not judge anything based on the listed talking points. Now, knowthing is impossible and such services are sure in the interest of governments around the world. I also want to remind people on the Swiss Crypto AG which sold compromised analog encryption machines for decades.
Unfortunately many Mullvad endpoints are blocked and slowed down too.