Valve has consistently offered refunds in these scenarios. They’re offering them for GTA V, and they also offered refunds for Monster Hunter when Capcom decided to switch their DRM bullshit and broke it on the Steam Deck. I think Valve has done their part.
I’m unsure if GTA V was ever Steamdeck Certified, but I imagine it might have to do with that. They may only offer this for games they said were certified and the devs broke it after the fact. I know Monster Hunter was.