Break up some of the chocolate-covered peanuts into smaller pieces, leaving some whole for texture variety. If using large peanut butter cups, chop them into smaller chunks.
Pour heavy whipping cream into a large mixing bowl. Use an electric mixer to whip the cream on medium-high speed until stiff peaks form, about 3-5 minutes. Be careful not to over-whip the cream into butter.
Pour the sweetened condensed milk and the vanilla extract directly into the whipped cream.
Gently fold everything together using a spatula until fully incorporated.
Reserve a handful of chocolate-covered peanuts and peanut butter cups for the topping. Fold the remaining chocolate-covered peanuts (both whole and broken pieces) and peanut butter cups into the ice cream base.
Pour half of the mixture into a 9×5 inch loaf pan or another freezer-safe container
Drizzle 1/4 cup of fudge sauce and 1/4 cup of caramel sauce evenly over this layer. Use a butter knife or skewer to gently swirl the sauces into the ice cream.
Pour the remaining ice cream mixture on top. Drizzle the final 1/4 cup of fudge sauce and 1/4 cup of caramel sauce over the top layer. Swirl the sauces to create a marbled effect.
Sprinkle the reserved chocolate-covered peanuts and peanut butter cups over the top layer.
Cover the pan tightly with plastic wrap. Place it in the freezer for at least 6 hours, preferably overnight, until the ice cream is firm. Serve in bowls or ice cream cones.