Heat 1/2 cup of the heavy cream until steaming, then whisk in the cocoa powder and chopped chocolate until smooth and glossy. Let it cool to room temperature.
Beat the cream cheese, powdered allulose, vanilla extract and salt until smooth, then beat in the cooled chocolate mixture until fully combined.
Whip the remaining 1 1/2 cups heavy cream to stiff peaks and fold it into the chocolate mixture in two additions.
Fold in the toasted almonds, mini marshmallows and chocolate chips, saving a small handful of each for the top.
Spread the ice cream into a loaf pan and scatter the reserved almonds, marshmallows and chips on top, pressing them in lightly.
Cover and freeze for at least 6 hours. Let it rest for 10 minutes before scooping.