There are three difficulties in "Stalker 2: Heart of Chernobyl", namely Novice, Stalker and Veteran. If you want to change the difficulty, you can open the pause menu, scroll down and select "Options" . Once in the options menu, continue scrolling down to select "Difficulty Settings."
How to change the difficulty of STALKER 2
You can adjust the difficulty of the game at any time. To do this, open the pause menu, scroll down and select "Options." Once in the options menu, continue scrolling down to select "Difficulty Settings."
After entering, you can choose "Novice", "Stalker" or "Veteran" as the difficulty. After selecting your difficulty, exit the menu and confirm your changes. Again, there may be times when the game's difficulty is too hard or too easy for you, so being able to adjust the difficulty at any time is a nice touch.
In addition, under the "Accessibility" tab at the end of the options menu, you can find more settings to further adjust the game's ease of use. If you're playing on PC and encountering performance issues, don't forget to adjust your graphics settings to improve game performance!