My son's switch lite is no longer working so we replaced it with a Nintendo switch but...

My son's switch lite is no longer working so we replaced it with a Nintendo switch but unfortunately when he logged into his Nintendo accnt on the device none of his downloadable content or game progress was saved. under settings he went data management saved data cloud and got error msg "unable to find data to display. only backup data not saved on console will be displayed" under transfer data it said he needs to transfer from the prior device but his switch lite device will no longer turn on. He had a Nintendo online accnt so we don't understand why none of this was saved on the cloud. * He spent a lot for his own money DLC and countless hours progressing in his games so he is very disappointed. *how do assess if it is fixable and how do we get his old switch lite fixed? we bought switches from gamestop but said they do not do repairs.