thanks a lot for all your help and advice, very encouraging as I played more with my raw images of the milky way. Depending on the original ISO setting and exposure, I have to use different settings in Raw Power, of course.
But my general approach worked as follows: Reduce Boost and Block Boost to 0.5, Luma and Color Noise pretty much all the way up, Raw Contrast to 0.5. With some images I used Definition and Deepen. Then Sharpen in the lower section to 0.5. Finally, I would typically apply a curve with lowering the shadows further and lifting up the curve in at 50% such that everything from 20% up would be lift above the diagonal. That would give the milky way and all other stars quite a bit more contrast. I accept the resulting artefacts in other parts of the image. That’s the price for not using stacking and special software packages to process those images.
In case anyone is interested, I can send a raw image plus a screen shot of my settings so you can replicate the process and see the results.