ElectricBlue My sense is that so far it requires much more developer labor but has not resulted in falling behind on Google's security updates. More developer labor presumably slows down GrapheneOS-specific initiatives, and I think the project has made posts counseling patience and suggesting some features may come more slowly than previously expected.
Overall I expect that if there are serious impacts on security then the project will say so. Meanwhile, I think it's too early to ask for the project's considered opinion of the impact, because they're still figuring that out. More will be known when the Pixel 10 ships, but probably not before then.
Please note that I do not speak for the GrapheneOS project.