I made an image noise comparison between the GH6 and the EM1Mk2.

Here we can see how especially in the regions below ISO 1200 the EM1Mk2 performs much better.
After that, the GH6 is ahead. At an extremely high ISO of 25600, the GH6 image is still “usable” after denoise, but the EM1Mk2 image is no longer usable due to the clear purple cast.
However, with the EM1Mk2 the details are more clearly visible than with the “mud” of the GH6.
All images were developed in Lightroom with the same settings.
The lighting and the subject have not changed during this time.
Since this is only about the noise behaviour of the images, the angle of view when changing cameras is not ideal.
The first image shows the entire image section, all others only a cropped section.