Pool/Spa Leak Falling Tile

My pool is 2 years old and has had a leak for about a year. I GC’d it all and have learned many lessons along the way. I recently had a leak detection company out for the 2nd time. They tested all the plumbing and it all checked out. I had all of the waterline tile replaced lastyear due to a crack in the bond beam all the way around. Water penetrated the grout line and created a mess. I live in West Texas so the high temps and freezing winters contribute to lots of movement in the ground and concrete. I have noticed that the spa will drain down to one of the return lines and stop. The leak detection company stated that these lines were good. The pool will leak down below the skimmer so I believe the skimmers to be good. I suspect that I may be losing the water under the granite bar top. The top sits about level with the pool skimmer throat so it normally has about 1.5” of water on it. The spa has lots of tile in it with only the joint pool wall and floor having plaster. When filled up, the pool will lose about 2” of water in 12 hours. I believe this is a combination between the tile and other leak. I need assistance in finding the main leak so that I can fix everything and move on. The tile has started falling again due to the fluctuation in water level. I have a ton of concrete deck so a noticeable ground leak is out of the question. Let me know your thoughts. I can post more pics and provide any additional information. Any help will be appreciated!