Frozen spinach will pretty much always have that cooked-down texture, especially if it is “chopped spinach.”
Squeeze out all the water, mix into into ricotta cheese along with one egg, and use in your favorite lasagna/baked ziti/stuffed shells recipe.
Or, squeeze out all the water, and add to alfredo sauce (a packet of boneless salmon is a good add too), pour over fettucine.
Fresh spinach is good to eat as is in a salad, or cooked VERY fast with garlic.