Try turning DRO on. It won’t do anything to the RAW files but it will brighten up the shadows in the viewfinder a bit.

The problem you are having is that the viewfinder/screen on mirrorless cameras generally shows you exactly what your photo will look like. If you have it set to expose for the sky then of course the shadows will be dark since that is what the photo will look like. Your eyes can see a lot more dynamic range than the sensor so of course an optical viewfinder will look better but it isn’t accurate. What I often do in high contrast situations is boost the exposure while I’m composing so I can see the shadow details and then drop the exposure to the correct settings before taking the photo.

This post has real “Old Man Yells at Cloud” vibes.