Puree all ingredients for the blueberry sauce in a food processor (it doesn’t have to be completely smooth), and set aside for now. The blueberry sauce will thicken slightly as it sits.
Unwrap the cream cheese, place it in a large bowl, and microwave on high for 30 seconds to soften it. Add the erythritol, vanilla, and stevia glycerite, and beat with a handheld electric mixer until smooth.
Beat the heavy cream to stiff peaks in a separate medium bowl. Beat 1/4 of the whipped cream into the cream cheese mixture until smooth. Use a rubber spatula to fold in the remaining whipped cream 1/4 at a time.
Transfer the mousse to 5 individual glasses or bowls and divide the blueberry sauce on top. Garnish each with 2 blueberries if desired.
Serve, or cover and keep refrigerated up to 3 days before serving.