Graphics options are fairly straightforward. If you’re having issues with performance, turn down the following:
Antialiasing can be turned off
Render sampling should be on native or in dire circumstances, subsample
Character Model Limit helps a lot when there are a lot of players/npcs in the area (don’t go below medium/low otherwise you’ll stop seeing certain boss AoEs)
Ambient Occlusion can be turned off along with Shadows for better performance. Shaders are probably the next to go, then LOD Distance
I prefer to limit my fps to 60 even though I have a 144hz monitor so my components aren’t working 100% all the time. You can use an external method of capping your framerate as well
There are new separate Postprocessing options. I personally turn the bloom off, but that's up to you