I think we all agree for the most part. It is Rafa's level that is not allowing him to compete near his best and allowing players that he had formerly dominated to turn the tables on him. To get his level back, he must do two things, practice very hard, and win matches against better players to raise his match level. If he can't do this, then he won't be able to compete and win consistently at the top level, simple as that.
So there are two questions I have that only Rafa, and maybe his uncle and team could answer.
1. Is Rafa healthy enough to work hard, or is there some condition holding him back from training as hard as he would like?
2. If he is healthy enough, does he still have the motivation to work very hard, or has he done so much already, that he doesn't want to devote his whole life to this anymore, and prefers a more normal life? In other words, leaving an hour or two a day to tennis, and then he enjoys his family, friends, and other things.
If he doesn't have either one of those 2 things then he is going to have inconsistent results and we shouldn't expect much more. Toni said it right, the only way to turn this around is through hard work in practice. There is no other way. And to do that, you need to be healthy and very motivated. If he isn't, c'est la vie.
Here is another thing. Players even at this level can have off years. He can always come back stronger next year if he puts in the effort. He is still under 30.
Respectfully,
masterclass