Went camping over the weekend. Dude pulls in with a travel trailed and f150 truck. Dude leaves in a second car, but lights stay on. Dude didn't come back til next day and of course battery dead.
This dude had no idea how to even open the hood of his pickup truck and was having a hard time looking in the owners manual for 10 minutes trying to figure out how to open. I never had a F150, but I still walked over and showed him how to open the hood. Then offered more help but he said we was good, and then saw him look and touch the engine with his finger for 20 minutes. I walked over and asked him what was wrong, to his response of confusion that his "truck broke" but he had no idea why (battery dead). I explained that I saw his truck lights on yesterday after he left and that his battery was dead, and he said "but this isn't an electric car"... He finally understood from another good Samaritan with junper cables what had happened and we both helped him get his truck started. I asked him how long he had this truck, and he said he's had it for a couple of years since new and always gave him problems, and I swear I am not making this up, one of those was that he ran out of gas.
All this to say that no matter how easy something might be for some, there will always be an idiot who can't even manage that.
I wouldn't trust any phone with GrapheneOS preloaded unless it was directly sold by GrapheneOS themselves. Especially not from a site that phrases things in an almost uncanny way.