The lens makes the difference.
The Leica 12-60 is an excellent lens and worth every penny. That's Leica for you.
The aperture value of the Leica lens is f2.8 - f4.0.
With the Panasonic lens it starts at f3.8 and goes up to f5.6 in the zoom range.
This means that at a focal length of 60mm, the smallest aperture for the Leica is f4.0 and for the Panasonic 5.6.
The Leica alone costs CHF 799.
Panasonic 12-60mm f/2.8-4.0 ASPH. Power O.I.S.
The Panasonic only CHF 372.-, that is over 400 roubles less.
Panasonic 12-60mm f/3.5-5.6 ASPH. Power O.I.S.
The premium on the Leica lens is more than justified.
I've shot some professional films with the GH5/Leica kit and was always very satisfied.

Aha! The difference can be found in the different lenses H-FS12060 and H-ES12060 (LEICA). Thanks for the tip! I gladly accept the small surcharge for the H-ES12060 (LEICA) lens.

The price difference could come from the fact that in one case the high-quality Leica kit lens 12-60mm is included, while in the cheaper case a Panasonic-owned kit lens 12-60mm is included. Based on several test reports, I decided to buy the more expensive version with the Leica lens. This offers very good image sharpness, which is not necessarily the case with the Panasonic lens. The camera is highly recommended for both photography and filming.