IMO there is no need to Look for reasons and conspiracy theories (Team Con let her sing in 2017 + her mic is on during some parts) - she chooses not to sing. She has almays lipped almost everything, even before the conservatorship. Baby voice or not. That's why I couldnt fully enjoy her tours at all. Is it hard to pre record New vocals? Lip syncing to CD vocals is pathetic. Fans are to blame too, Britney could always get away with that.
Plus she doesnt have to dance all the time, people would praise her for live singing