The only 5N we've done did not have a formal night. There was a semi-formal night and Pirate night. All the others were "cruise casual".
You can talk to DCL as your cruise gets closer and they will tell you the attire for each night. But, what I like about DCL is there is not any pressure to get dressed for dinner. I personally bring a Tux if there is a formal night, but many people will wear a suit jacket, or just go "cruise casual".
Currently, there are no formal or semi-formal nights on the Magic. You can dress up on your own, but you will have to get your pictures taken with masks on and with distancing from any characters.
GET UP TO A $1000 SHIPBOARD CREDIT AND AN EXCLUSIVE GIFT!
If you make your Disney Cruise Line reservation with Dreams Unlimited Travel you’ll receive these incredible shipboard credits to spend on your cruise!