Problems with color, saturation and contrast in Lightroom

During import of RAW files LrC uses the JPEG preview embedded in the file by your camera. When file arrives in the Library module the preview will adopt the Adobe rendering rather then your camera vendor rendering. However, if you choose to import the files using the 'Embedded & Sidecar' option in drop down menu at top right corner of Import window, then trhe Library preview will remain as per the camera vendor rendering. 

For raws, LR has to build its own unique and proprietary previews. The initial preview you see is the embedded JPEG from the camera. So this is to be expected. 

Not for rendered images (JPEGs, TIFFs) however. So if that is the case, there are two areas to look into:

First, try disabling GPU in the preferences (Performance). Any better?

If not, recalibrate and build a new ICC display profile; the old one might be corrupted. If you are using software/hardware for this task, be sure the software is set to build a matrix, not LUT profile, Version 2, not Version 4 profile.

If turning OFF the GPU works, it's a GPU bug, and you need to contact the manufacturer or find out if there's an updated driver for it. This is why disabling GPU is an option as more and more functionality moves to the GPU in newer versions of many Adobe products.

Also see: https://helpx.adobe.com/lightroom-classic/kb/troubleshoot-gpu.html

If the GPU and display profile isn't causing the problem, see:
https://helpx.adobe.com/lightroom-classic/kb/lightroom-gives-error-preview-cache.html