Export image quality

Hi, first nice to see you all here! I am new to this forum. My Google search actually led me to this wonderful site.

I found quality of every exported image is always being compromised in terms of dynamic range, shadows and overall quality.

Original file is mostly from GoPro. 4k
I exported those files as 4k UHD, MP4 and h264. The exported files always look like contrast is increased, gamma is reduced and noise is increased in the shadow. I don't know why it does its automatic adjustments. Maybe, it may be a sign that I am doing something wrong to lower the quality of the original files. Please help me out!!

Try to export in a better codec, like DNxHR or Cineform. Does it look better?
If not, you need better monitoring with an I/O card and a calibrated monitor to see what you are doing in Resolve.

We need to start with a proper viewing environment. There's a method that has to be adhered to, otherwise you may not be seeing the image as it really is, but altered in some way.

Simply put, you have to take the computer out of the signal chain and view the image on a calibrated display. There are a couple ways to do this.

You can add an I/O card from BMD, like a Decklink. Feeding that to a properly calibrated display will bypass various computer variables and ensure that you're seeing the image accurately within Resolve.

For accurate viewing out of Resolve, you have to move the export off the computer and play it on a calibrated display from a hardware device. Burning a Blu-ray, for example. Or playing from a thumb drive.

The one thing you can't rely on is watching the video, either the original or the export, on the computer.