we have a guide in the making for replacing the D-pad. It should be live soon.
There you’ll be able to see the build of the D-pad and can experiment with different “mods” to it.
In the meantime you could bend the metal spring that pushes the pad back up to your liking or you might want to add a thin extra layer between the pad and its rubber part so the connectors on the rubber part make contact with less travel.
Good luck with finding the sweet spot and think about sharing any findings for others to learn and improve their gamepad from.