Building a second Dmax Blissey?

I’m thinking building second dmax Blissey must have been worth it right? I’m using dmax Blissey almost everytime together with gmax Snorlax (both level 40 with max heal and max shield). But after several dmax legendaries or gmax event, I notice my gmax Snorlax with three shield often get one shotted most of the time.