A seized device wouldn't be able to be protected well against threat models anyway, because seizure of the device means they can prevent it from updating, only increasing the chance of an entry with time as the device becomes more and more insecure.
If your device is seized it's essentially a ticking clock, the more secure the device, the longer the time will take.
Furthermore it's not really a good idea to correlate GrapheneOS to criminals. GrapheneOS is not or ever will be for those people, even if they can benefit. This is my opinion but the existence of GrapheneOS is beneficial to anyone, preventing them from being victims of all sorts of crime. It is a privacy/security project which makes criminal markets fall and can be used to protect others from being a victim of certain attacks. Why do you think the GrapheneOS project and team have enemies and attacks towards them - sometimes a threat to their lives? Some criminals hate GrapheneOS.
Before this project there was never a truly secure mobile operating system project and the only market was google-free Android distributions with tons of security issues or some piece of shit security theater cellphone that criminals would sell to others like EncroChat and SkyECC, which worked with organised crime then get breached later. GrapheneOS invalidates this entire market's existence. Some that aren't criminal will straight up sell you snake oil or false security, and some will even start selling (sometimes fake) GrapheneOS phones themselves because they know they can't compete.
Buying garbage like that helps criminals selling it by you giving their money to fund their illicit activities, while using a free and open source project like this on your phone doesn't. Not to mention scenarios of GOS protecting you against an abuser, cyberattacks, or abuse of your data from companies also...
Criminal actors, if they are getting caught with a GrapheneOS device likely have enough evidence to convict them anyway, because why would that phone be the only evidence they have? Most crimes are essentially done in the open and always involve people trusting other people not to tell on them, no phone can protect that. And when it's a serious crime like homicide there is so many forensic vectors that you'd essentially need to be in an incapable to enforce area or be corrupt to even get away with it. GrapheneOS cannot help criminals.
GrapheneLover Depends on your threat level but if you want the honest truth we don't really know what advanced methods law enforcement or government agencies and contractors have available
This. All you can assume is advertising, leaks, and news. Trying to protect against a seizure is hard luck. They have time to wait for a vulnerability.