Bottom line your camera exposure settings do matter. The key word EXPOSURE. The Focus does matter. These 2 things effect the sensor and how much light it gets and how sharp the image is. That is what is limited to about + - 3 stops in processing. Everything else is just what the little computer adds. Believe it or not Photoshop Lightroom Gimp can tweak the shot to bring it to what your minds eye saw. These can't make up for poor composition, out of focus, piss poor light.
All this stuff combined can make the difference between a snapshot and a great shot

Brights highlights and shadows have nothing to do with W/B That is the dynamic range of the sensor. The W/B is the overall color of the scene and what white should show up like. Have you heard of the Golden Hours for shooting?

I am new here but with allot of experience. I shoot outdoors for animal studies and do some landscapes. Most of my shots are technical and environmental. This is just for a little background.
Leave the camera on auto white balance. The camera does a pretty good job of getting it right. When trying to catch a critter on the move I'm not going to sit there and fiddle with W/B. There is nothing I have found to date that Light Room cannot correct with the W/B if the camera is left in auto. There is also how you like your pictures. I mostly tend to the warm side. So I tweak it. Once in awhile I go to the cool side as in a winter scene. That is the art of the shot. There is no right or wrong, just personal preference.
The goal that you should try for is, Do as little post processing as possible. If you are going for the artsy effect then you will spend more time in post. The cameras sensor just won't have enough dynamic range to catch the scene. Just can't do it. What you see on your screen when you take a raw picture is actually a Jpeg. What you see when you download your image to Lightroom is also a Jpeg that is rendered from the raw file. When you actually go into the develop mode that is when you see the raw image. Flat no sharpening etc.