Have you tried Hoka One Ones? They are probably one of the best cushioning soles you can get. But keep in mind, that much of cushioning can be bad for tennis, especially if you are a good mover on court. On stop and go for side movements, the higher soles can cause instability and cause injuries. But if you don't move aggressively sideways, and just want to use as much cushioning you can get, go for it.
Otherwise, go with something like Adidas Solecourt Boost, which is more tennis specific, and so even though does not provide as much cushioning as "Hoka One One", still does provide enough, and with stability for tennis.