Gherkins is right
Fortnite can be downloaded on to many devices like a phone, xbox or play station (in my case a switch). When you get fortnite you make an epic account. This is the account that you sign into when you go onto fortnite on a new console. When you log into your epic account it will 'wire across' your fortnite account leaving you with all your possessions, dances and statistics. So no, no details are lost because they'r esaved in the "cloud" on your epic account.