GrapheneOS themselves dont pretend that their secure from that level of attack, but its about evaluating your own threat level. State sponsered actors aren't burning zero days on the vast majority of people, and you only need to look at how badly several european governments want to ban graphene and similar to see that such exploits aren't even being burned on organised crime. Realistically unless you're a journalist or considered a political target you're gonna be fine with graphene.
Thank you for the insight. Indeed, a concerning state of the world where criminals are less at risk from spyware than journalists and activists.
Its definitely a scary world, safe to assume all your online activity could be hacked if so wanted. Just gotta hope its not wanted and that it doesnt become possible to do it on a mass scale (UK is currently pushing to ban E2E lol, and I know the EU has contemplated similar. If you do fall into the wanted category, face 2 face is really the only option. I know a lot of politcal/investigative journalists also constantly cycle and maintain burner devices but even thats a risk of just how long is a safe time before a device is considered burned.