Using the default settings, the game will drop to 40 fps outside of the ship (60 Hz). A way to fix this is to remove vsync in-game (In Settings, under Display -> Frame rate cap). From Use monitor (V-Sync) to 120 fps or higher. If vsync is desired, use the Deck's framerate cap + vsync. I am also running the HDLethalCompany mod (https://github.com/Sligili/HDLethalCompany) in order to specifically lower shadow quality, which is High by default and it cannot be changed in-game. With these settings, the game hits a stable 60 FPS outside of the ship in Experimentation (was 40 before tinkering) and a stable 60 FPS inside the building, but drops all the way to 35 FPS inside the ship. Tested in an empty lobby hosted by self.