Don't mess with anything, set the quality settings in games, and what setting there would depend on the game.
With that PC you should be able to run games on High presets at 1080 and probably 1440 resolution.
Yes. I have never changed default Windows settings on any of my systems that I can remember. One of my top computer ideas to use is "don't try to fix something that is not broken or you are likely to break something". Leave things at stock settings, unless you have issues or things are really not working like you think they should. Then research for a while why something does not work properly, then try some small things one at a time to fix that. Just looking to change settings before using the system is only asking to have things crash or do something odd before you even start.
Usually we see posts like this: "I just built a new computer and changed the thermal paste and added water cooling and overclocked it and uninstalled things in Windows and now it does not boot".