Hi Oronzo,
First things first, you need to change the Form Key in your Human Task from embedded:app:forms/approva-richiesta.html to embedded:deployment:approva-richiesta.html since you are deploying the html file along with your bpmn file without packaging it in a project. There seems to be something amiss in the html as well which is preventing it from rendering. If I put in something simple it works. I’ll have a closer look at the html but in the meantime, update your Form Key.