Preheat the oven to 350 degrees F (175 degrees C).

Mix sweetener, peanut butter, and cream cheese together in a small bowl until filling is smooth. Spread peanut butter filling onto the bottom of the pie crust.

Place chocolate in the top of a double boiler over simmering water. Stir frequently, scraping down the sides with a rubber spatula to avoid scorching, until chocolate is melted, 3 to 5 minutes.

Place sweetener and cream cheese for chocolate filling into a small mixing bowl. Beat with an electric mixer until soft. Add milk slowly; mix with a wire whisk until smooth. Add melted chocolate. Stir well. Add eggs and vanilla extract; mix until well blended. Pour into the pie crust on top of peanut butter mixture.

Bake in the preheated oven until set, 20 to 25 minutes. Chill for about 2 hours before serving.