In principle, it is of course possible to do the tour in one day, but the timing is not so easy. In the typical tour time, you will hardly be able to ski down in good conditions after the cable car opens. It's more relaxed if you either spend the night in the Berghaus Diavolezza and start early the next morning, or set up camp in the (rather spartan) winter room of the Marco e Rosa hut. From there, you can take a relaxed approach to the summit and are probably still alone at the top, as you have a decisive head start on the ski tourers (who often turn up en masse at the weekend) who start from Morteratsch station or the Boval hut.
Ascent
The first part of the ascent is easy with the gondola to the Diavolezza mountain station. From there, the route leads up a steep and rocky south-western slope to Vadret Pers, where the first ascent begins at an altitude of just over 2,700 meters. Climb over the glacier in a large, flat arc, first to the southwest, then further west, past the three northern pillars of Piz Palü in the direction of Fortezzagrat. It gets a little steeper towards the ridge, but the ridge can usually be reached without any problems. Follow it a little to the south, then you have to decide how to proceed.
You can either follow the ridge further south (not easy) until you reach the Bellavista terrace and cross it to the west before descending briefly to the Vadret da Morteratsch and from there ascending to the "Fuorcla Crast'Agüzza" (alternatively, the Bellavista terrace can also be reached via a small glacier break a little to the west of the Fortezza ridge). However, you can also descent a little to the west from the Fortezza ridge to the Vadret da Morteratsch (unclear) and ascent through the "Buuch" glacier break. Afterwards, keep to the west on the flatter glacier, then to the south and finally to the southwest and you will also reach Fuorcla Crast'Agüzza.
