This seems very unusual. I tested the game myself on an i5-3570K, 16GB RAM, and an RX 580 8GB, and my lowest FPS was around 30 FPS, no matter walking or standing. In hotel it could reach 100 FPS.
So, You said "I turned down all the settings as much as I could." And, maybe you change Vsync settings in a bad way.
First of all, Close the game. Go to "S_O_S_SeasonOne_Data > Data > Config. Then, DELETE the file named "GameOptions.json". (GET A BACKUP FIRST, THEN DELETE.) Then launch the game again. It will reset your settings.
Because you're getting around 60 FPS while standing still but dropping to 25–45 FPS as soon as you start walking, I don't think we should immediately assume that the hardware isn't powerful enough. This kind of behavior can also be caused by settings or something being triggered while the player is moving.
Could you please check the following:
- VSync: Make sure it is configured correctly. VSync can sometimes cause large FPS drops when the framerate falls below the monitor's refresh rate.
- Render Scale: Make sure the Render Scale isn't set higher than 1.
- Resolution: Make sure the game is running at your monitor's native resolution and that there isn't any unnecessary resolution scaling.
- Smooth Looking settings: Please check the settings related to Smooth Looking and try disabling them temporarily to see if it changes the performance.
- Monitor refresh rate: Check your monitor's actual refresh rate in Windows and make sure the same refresh rate is selected in the game.
- Shadows: Try lowering the shadow distance temporarily. Shadows can be particularly demanding in this game.
- I just want to rule out a configuration or game-system issue first, because an i7-10700 + RTX 2060 + 16GB RAM should be significantly more capable than the hardware I used for testing.