m43 Studio portrait RAW-file?

One difference in jpeg vs RAW performance under careful lighting conditions (or any conditions)  is that for Olympus at least, even if you have Sharpening set at -2 then some small degree of sharpening still happens in-camera.

So for super-critical evaluation of camera/lens/image quality then RAW is always needed. Plus of course a decent RAW converter to make the most of that RAW file. Plus a properly calibrated IPS monitor etc etc.

Regards....... Guy