Hello Massimo and welcome.
Your garden sounds wonderful.
Yes the idea to save compost on the pumpkin bed by spreading it around only the plants is good. Using other mulches on the rest of the area is a kind of sheet composting, still good for the soil though I expect the harvest to be less.
Also in a northern climate, its good to use compost near plants that need to establish fast in early summer. Spreading it on the whole bed has this effect too, but you are being more economical.
Happy gardening.