Given how many years people is answering LineageOS or GrapheneOS, I would like to state that "LineageOS" or "Graphene" means Android.
Yeah, those are all android under the hood.
Maybe customized to various depths and details, but still it's android.
It's much more correct to say that Lineage or Graphene are Android than saying that Android is Linux.
Both Lineage and Graphene would not exists and could not exists without Google developing the AOSP.
While they improve stock Android quite a lot, they are still Android.
I stress this because lots of people think that those could be alternatives to Android and the Google monopoly, but it's not true. Only a true Linux mobile OS would be.