Spray a 9 x 13 x 2-inch baking dish lightly with nonstick cooking spray and set aside.
Combine 1 cup water with 1 cup reserved pineapple juice and heat it in the microwave for 1-2 minutes, until boiling. Add it to a medium bowl with 1 (6-ounce) box lime gelatin and whisk until the gelatin is completely dissolved. Set it aside to cool for at least 10 minutes,
Add 8 ounces softened cream cheese to a large bowl and use a hand mixer or stand mixer fitted with the paddle attachment to beat the cream cheese until smooth. Take the time to scrape down the sides and bottom of the bowl and beat it again, ensuring that there are no lumps of cream cheese remaining.
Add the cooled gelatin to the cream cheese and carefully mix until completely combined.
Slowly add 1 cup 7-Up Soda to the cream cheese mixture to ensure it's evenly incorporated and there aren't any lumps. Add 1 (20-ounce) can drained crushed pineapple and mix until combined.
Whisk in 1 (8-ounce) container thawed whipped topping until smooth, then pour the gelatin into the prepared baking dish.
Cover with plastic wrap and chill for at least 4 hours, or until completely set. Serve with additional whipped topping or whipped cream.
Notes
Leftover Instructions: Store leftovers tightly covered in the fridge for up to 5 days—skip the freezer, Jello doesn't thaw well.