It sounds like you are looking for a way to take higher quality screenshots in your game without sacrificing performance. One possible solution could be to use a third-party program or tool to take screenshots of your game. There are many options available, such as OBS Studio or Fraps, which can capture high-quality screenshots while the game is running.
Another option is to use the built-in screenshot functionality of your operating system, which can be accessed by pressing a hotkey (such as "Print Screen" or "Win+Print Screen" on Windows) or by using a screenshot tool. This will capture an image of your entire screen, which you can then crop or edit as needed.
Alternatively, you could try pausing the game and manually adjusting the graphics settings to take a screenshot, as you suggested. This can be done through the game's settings menu or by using a third-party tool such as GeForce Experience, which allows you to adjust the graphics settings of your game while it is running.
Ultimately, the best solution will depend on your specific needs and preferences. I hope these suggestions help you find a way to take high-quality screenshots of your game without impacting performance too much.