Graphene isn't the only option to DeGoogle. Depending on your model you may be able to unlock your bootloader and run an AOSP based rom. I run Android without Google apps and services on my RealmeXT.

I actually went with the Pinephone instead of the Librem5 and run Arch with PHOSH. I personally don't think the Librem is worth it's price tag. Eventually I plan to pick up a Pinephone Pro or maybe a used OnePlus 6(T) to run mobile Linux.