Well - had the same problem. Now I have a mask with glasses (Varilux / for near and far away). With the 45° viewfinder it was really good. But now I have a external monitor on my housing. => no problems anymore! You see everything (small critters or tiger sharks) without problem. You can do super easy video or you can push your cam in a hole and still see your subject easily on the screen. - no stress anymore.
Good luck !