You seem confused. Copperhead AFAIK existed since 2015. Daniel was fired in 2018. GrapheneOS has existed since 2020 when it was officially named GrapheneOS. It was named Android Hardening before that in 2019.
You can't conflate CopperheadOS as GrapheneOS or vice versa because GrapheneOS has changed over the years since the split. I think the ex business partner makes this same mistake.