We did a week in Cortina and then several days in Arraba. Cortina is a fantastic ski town with some good skiing and great eating. Hire a guide and do the Bus de Tofana. A 9000 Vert run that requires some mountaineer to get thru the hole onto the backside of the Mt. Cortina is very Italian.
Then in Corvara and Arraba is more Germanic. I think the skiing is better in this huge region. More alp like. I dont think the sellaronda is worth doing as I prefer to not rush thru the day on a set timeline or face a long bus ride back to where you started. You can still ski all the components in a week just taking more time to explore.
The negatives are Italians do not believe in civilized lift line behavior. It’s totally ever man for themselves in those lift lines especially on a weekend. Italians constantly chain smoke even while skiing. It’s also mostly above treeline so if you get weather the days agenda becomes eating not skiing. If that happens go to one of the lower tree lined areas ski a bit and have a 2+ hour lunch which is what most Italians do on thier ski days regardless of the weather.
Everyone should ski in the Dolomites for a week at least once on thier life bucket list.
if You French Fry when you should Pizza you are going to have a bad time