Preheat oven to 350°F (175°C). Crush pretzels to fine crumbs. Mix with melted butter and 3 tablespoons of sugar until evenly coated.
Press firmly into a 9x13-inch (23x33 cm) baking dish. Bake 10 minutes until set and lightly golden. Cool completely, at least 30 minutes.
Beat softened cream cheese and 1 cup of sugar with a hand mixer on medium for 2 to 3 minutes until smooth. Fold in whipped topping gently with a spatula.
Spread cream cheese mixture over the cooled crust. Cover every edge and corner completely. Refrigerate.
Dissolve both gelatin packets in 2 cups boiling water, stirring 2 minutes. Add strawberries and syrup. Cool at room temperature 25 to 35 minutes until lukewarm.
Pour cooled gelatin over the cream cheese layer. Refrigerate at least 4 hours until fully set. Overnight gives the best results.
Run a knife around the edges, cut into 12 portions, and serve cold.