Lineage and a fork, DivestOS are very close to Graphene, and run on far more devices.

The search for perfection is the enemy of good.

I've run Lineage for years on some spare devices. Battery life is so much better without Google Services.

My most recent device (Pixel 5 with DivestOS) is averaging 1.1% battery consumption per hour over the last day. That included an hour of navigation, using Google maps with microG services.

One old device runs longer with DivestOS than it ever did with stock, and the battery has lost 40% capacity. That's how bad Google Services eat battery.

Plus Lineage permits you to use a number of old devices, unlike Graphene. It's good, it gives you far more control than Google.

My final thought on Graphene - it needs to be taken over and lead by some professionals. Those folks act like stereotypical geeks of 30 years ago, arrogant, condescending (I worked with their type 30 years ago, and was a little like them then). They also denigrate anything less than what they deem "perfect". The very definition of hubris.

Their attitude is "if you have a problem you must've done something wrong, why did you do something wrong". Having that experience with them has put me off Graphene permanently.

Edit: I can re-lock the bootloader with Divest, so the condescending Graphene folks are just plain wrong about being the only OS that can do this. I don't lock it, because my threat model doesn't require it. The odds of my phone being grabbed by someone with state-actor-level skills being after me is non-existent, and there are easier ways to get the same data from me.