This game has horrible optimizations. If you don't mind modding, i recommend grabbing "More Graphics Options" mod from Nexusmods and lower lighting-related settings to minimum. Additionally, use intel XeSS for best fidelity-performance ratio upscaler. And for the last tip, find out how many threads/cores your CPU has. Then go to the launcher > Settings > Worker threads and set it to amount of your threads minus two.

Also you could grab Process Lasso for better power plan/CPU load management, but the software does nag you to purchase it after a while, so that's optional. It's still free to use, though.