I just did a similar move: new z390 mobo, 9600k, ram etc. I did not uninstall anything, just installed the new mobo drivers once the upgrade completed. For the Windows - obviously it got de-activated after the upgrade, but retrieving a license from the Microsoft account (https://scottiestech.info/2017/02/26/upgrade-your-motherboard-without-reinstalling-windows-10/) did not work for me by some reason. It was around a midnight, but I gave it a try - called Microsoft support, and surprisingly they were able to reactivate it within like 5 min :).