Shadow quality is a major one. Fancy things like ambient occlusion as well.

You can try running with Vulkan if you aren't -- but the results can vary from a massive fps boost to constant crashing or lower fps.

Play around with the settings and watch how much each one affects your fps. That's how I optimised my settings.

Take off Chromatic Abberration, Depth of Field and Anti Aliasing, then drop vegatation to medium in the graphic settings.
Those will give some FPS and not make the game look bad.

Game will suffer FPS loss the more you terraform, to check this press F2 in game to see the number of instances , the more the harder it hits FPS.

Thats all I got.

Draw distance/level of detail, shadows, SSAO, and resolution have a big impact on frames.