Thank you very much for your tips. I already have the 6600. Since I'm not a professional, I don't want to spend more than CHF 400. Which lenses are recommended in this price range?

However, one may wonder whether the A7 III with the 24-105 would not be the better choice, because it is not much more expensive....

The new 16-55 f2.8. This also delivers very good quality and is universal: Sony E 16-55mm F2.8 G

This is my "always on" lens: https://www.digitec.ch/725698