I totally get your struggle with soggy galettes!
Make sure your dough is super cold before rolling it out and baking it. Avoid overfilling, as too much moisture can make the crust soggy. Pre-cooking fruits and tossing them with cornstarch helps too. Don’t forget to leave some space for steam to escape, and bake at a high temp (around 400°F/200°C). Preheating your baking sheet can also help.