I've got this issue on my note 10 plus apparently there is WiFi calling installed if you go to apps and like where you force close them and like disable apps area ! click show system apps and WiFi calling is installed !
but I'm having the same issue to ENABLE IT !!!!
WiFi calling with smarty sim works on my iPhone and works on my other andriod but there's no option to ENABLE WiFi calling on the note 10 plus ! think there's a bug in the Samsung software somewhere !