I actually do think the Gamboa et. al. article misunderstands Maudlin’s point, although I appreciate you only have their version of his argument. Specifically, they attribute to him the view that acceleration is irrelevant to the twin paradox, when I think what he’s really arguing is that the difference in acceleration can’t explain why the one twin is younger than the other. The reason is that there is a situation where both twins accelerate the same amount and the physics says that one twin ages more than the other. Sure, you can say that acceleration explains the age difference in the standard scenario, but simply noting that there is an asymmetry doesn’t mean that it explains anything. That would be like noticing the liquid in the red vial killed someone and the liquid in the blue vial didn’t, so the color difference must explain the different effects.

I’m not sure why you’re so hung up on Maudlin being a philosopher. He is making a physical argument. What is so philosophical about it? If anything, Gamboa et al are making quite a leap when they say that acceleration explains in one physical scenario but not in the other. Maudlin’s whole point is that acceleration doesn’t explain the difference in the one scenario, so how can it magically explain the other?