FWIW, as someone who is not in the phone OS development world at all but has been reviewing phones with alternative OSes for about the last 4 years...
My impression is that everyone else in the phone-OS and deGoogled-Android world hates the GrapheneOS folks, and it's mutual. They seem to be borderline impossible to work with, very arrogant and protectionist, and the project's own support lifetime is "when Google no longer supports your phone, we don't either."
Personally, I'd choose something else. Anything else, in fact.