While I admire GrapheneOS and its goals, I feel that until we free the proprietary baseband processors and their RTOS from the grips of Qualcomm and friends it's a pyrrhic victory, at best.
Don't allow perfect to be the enemy of good.
iirc Graphene is in talks with an unnamed HW vendor to make a grapheneos specific phone. They refer to the vendor as someone who makes phones and you've likely heard of, but haven't given any more info otherwise.
That and blocking the query all apps feature on android
Do you also need the WiFi chip to be fully free?
When there isn't a perfect solution, the next best thing is... the next best thing :-).