In a large skillet, heat the olive oil over medium heat. Add the chopped spinach and cook until wilted, about 2-3 minutes. Remove from heat and let cool slightly.
In a mixing bowl, combine the Greek yogurt, cream cheese, and mayonnaise. Mix until creamy and smooth.
Add the cooked spinach, chopped red onion, minced garlic, lemon juice, paprika, salt, and pepper to the bowl. Stir until everything is well combined.
If using, gently fold in the crumbled feta cheese for an extra layer of flavor.
Transfer the dip to a serving bowl and cover with plastic wrap. Chill in the refrigerator for at least 30 minutes to allow the flavors to meld.
Serve cold with an assortment of dippers such as pita chips, fresh veggies, or crackers.