The sharpening is just the default display setting for ProRAW files in many apps. If I edit a ProRAW file in Lightroom and turn down the sharpening and denoisin

The sharpening is just the default display setting for ProRAW files in many apps. If I edit a ProRAW file in Lightroom and turn down the sharpening and denoising then it looks roughly as you’d expect (though there is some denoising inherent to multi-shot blending). It’s a tricky one, because when you’re aligning and stacking multiple captures, you definitely do want some sharpening (as the result is significantly softer than a single capture would be). But the default is maybe a little aggressive.