Hi,
Mine is a sunken pool. My builder suggest to demolish the boundary wall n when he build the the concrete wall - like a “frame” for pool, the boundary sits on one side of the frame so that the pool is like glue to the wall. Can visualise? U save 0.3 or 0.4m there. The other side will have 0.3 or 0.4m ( cant remb) as the other side of the frame n 0.6m as walking deck. Ours is an old house in original state so to prevent future problems due to the stress of the pool, we do it from scratch.