> Also family of four: we fill a 120l garbage bin per week

What goes into this since you already recycle bio, cardboard, plastics and metal? My "generic trash" is a 25 liter bag that I empty about once a month or so. Since most things go to the specific recycling containers, the generic waste is dominantly just napkins and tissues that shouldn't go to bio.

I don't have kids so no diapers or anything like that, but 120l weekly sounds still a lot after recycling.