Place strawberries in a food processor and blend until a smooth puree is formed; strain through a fine-mesh sieve if a seedless texture is preferred.

In a small heat-proof bowl, combine cold water and gelatin powder and allow to bloom for 5 minutes.

Gently heat the bloomed gelatin in a water bath or microwave in 10-second intervals until completely dissolved and clear.

In a separate large bowl, whisk together the Greek yogurt, protein isolate, agave nectar, and vanilla extract until the mixture is homogeneous and no lumps remain.

Temper the gelatin by stirring in two tablespoons of the strawberry puree, then combine this mixture with the remaining strawberry puree.

Slowly fold the strawberry-gelatin mixture into the yogurt base using a silicone spatula until the color is uniform and the texture is light.

Divide the mousse into 4 chilled serving dishes and refrigerate for a minimum of 2 hours until the structure is firmly set.