Combine cream cheese and heavy cream in a bowl; beat with an electric mixer until smooth. Add erythritol and vanilla extract and continue beating until light and fluffy and stiff peaks form. Transfer mixture to a piping bag fitted with a tip. Fill the core of each strawberry and about 1 inch outside the core with cream cheese filling. Place on a plate, cover, and refrigerate strawberries until filling is chilled, at least 1 hour or up to 2 days.