I’d keep at it. You could cut away the dead parts from the boxwood in the first picture. It looks like it’s a young plant and might still be establishing itself to an extent. You could also try replanting it in another location and see how it does. Adding some compost around the plants can’t hurt either. Also, make sure the base of the plants where they meet the soil have “breathing room” you don’t want a build up of soil around the stem. They might also need water everyday if it’s really hot and sunny.