GrapheneOS duress PIN could land a man in prison

If he hadn't given the authorities the duress pin, and presumably they had seized it, would the encryption/protection GrapheneOS provides have been enough to keep them from accessing it's contents? I've never used Graphene so I'm unfamiliar with all it's features.

My Samsung phone has a feature to automatically format the device if the wrong code is entered X number of times, and I have security software that would let me wipe it remotely (if it still had internet access) so this whole situation brings up a lot of questions about features like this.

EDIT More discussion about it here, but it's quite technical. I was a bit confused about the rate limiting stuff and etc.

GrapheneOS protections against data extraction from locked devices - HN Post https://news.ycombinator.com/item?id=49055169

Just like when India banned Bitchat, this proves GrapheneOS works and you should use it.

Doesn't make sense to me to undermine the right to refuse information. From my POV dictatorships try to do that, not a rule of law.