CRUST: Combine pretzels and sugar in a food processor and process until fine crumbs. Add melted butter and process until coated. Place in a 9 inch glass pie pan and spread the crumbs to coat the bottom and sides of the pie pan including the rim. Once distributed, press down firmly and refrigerate or freeze until cold.
Cook frozen strawberries in a large saucepan over medium-low heat until they begin to release their juice, about 3 minutes. Increase heat to medium-high and cook, stirring frequently, until mixture is thick and jam like and measures 2 cups, about 25 minutes. Make sure you have 2 cups, if not, continue to cook until it has reduced to 2 cups.
Combine lemon juice and water in a small bowl. Sprinkle gelatin over lemon juice mixture and let sit until gelatin softens, about 5 minutes. Stir 1 cup sugar, salt, and gelatin mixture into the cooked strawberry mixture and return to simmer, about 2 minutes. Transfer to a bowl and let cool for 30 minutes.
Fold fresh strawberries into filling and spread evenly in the cooled pretzel crust or cooled cooked regular pie shell. Cover pie with plastic and refrigerate until set, at least 4 hours or up to 24 hours.
With a hand held mixer, beat the cream cheese, vanilla, and remaining 3 tablespoons sugar until smooth. Add cream and whip until stiff peaks form, about 2 minutes. Dollop individual slices of pie with topping and serve.