Having the fire take a huge chunk of the screen like this right here instantly removes like 40 fps. What setting is likely culpable? (ignore the very low quality of the screenshot)
I think Particle Quality, Particle Lighting and Global Illumination. I'm not sure how much or if the volumetric settings will have an impact on this, but you should definitely start with those settings.
What specs do you have? I have a Ryzen 5 3600 with 32 GB of 3000MHz CL15 DDR4 memory and a GTX 1080 Ti.
I have my Lighting Quality set to Medium, Global Illumination set to High, Particle Quality on Medium, Particle Lighting Quality on Ultra, and all Volumetric settings on Medium with Unlocked Volumetric Raymarch Resolution set to Off.
Particle, lighting and dynamic shadows would be in full effect there
Shadows is another thing too.
I recommend starting with the settings I said. With the settings I mentioned, decrease yours until you gain performance. If you don't gain performance, set it back to what you had and move onto the next setting. It might also prove to be beneifical to decrease a combination of settings.
You might want to leave the Particle Quality setting for last as you have to restart the game if you change that one, or maybe even change it first.
Alternatively, you could just use my settings and work your way up or down from there.
I would also recommend making a save by a campfire like that one, so you can load the game and go back to the campfire if you change the Particle Quality setting.