@emacsomancer have a screenshot? Haven't used Lineage in a while but IIRC at the time they just used whichever was higher which seemed very unethical. So if they show both that's definitely a huge improvement.

But regardless, I'd be willing to bet the vendor security patches are far behind. The main reason Graphene is more secure is because it forces you to use a Pixel, which is objectively more secure hardware.