There are not many Italians visiting this forum
All CO2 lasers can cut and engrave, BUT the ones that are optimized for cutting are not good for engraving and vise versa. You will have to decide on your priorities. From your list the Nova24 is best for cutting. These models of Trotec and Epilog are for engraving.
If you can provide a more detailed description of your projects (sizes, materials, thickness, etc.) and your budget you will get more specific suggestions. Basically try to define your production specifications and acceptable tolerances - what is good enough for you and what is not. Keep in mind that not all materials are safe to process with a laser. Some will produce toxic fumes when processed.
My general advice is to be patient, learn as mach as you can for the technology on a component level and when you fill confident make an educated choice yourself. Don't relay too much on recommendations as no one will know exactly your needs and there are no universal answers.