Resolve is ultimately more powerful than AE for grading, but it is a very different way of working as it uses nodes instead of layers.
I’ve not used Windows PCs for over 10 years, and I don’t have any crashing issues with Resolve on my computers (iMacs & Macbook Pros), so it’s possible it’s more of a ‘windows thing’. Have you tried non-Pro Res source material? As Pro Res is not native to Windows there may be a struggle with trying to constantly re-render changes to a non-native format, particularly in your CPU. Have you tried creating proxies to work/edit from?
I’m not sure what you mean exactly when you talk about contrast. Are you trying to adjust the curves?