But there's one thing you haven't taken into account.
Unlike Ted Kennedy (or any other past President), he'll be targeted with multiple criminal prosecutions as well as civil lawsuits the moment he leaves office. The crimes he's committed while in office won't magically disappear. His eleven felony counts of obstruction of justice, his refusal to comply with House subpeonas, his disdainful disregard of the emoluments clause of the Constitution---all those are serious crimes, and he'll be held accountable.
Also, don't forget, whatever shield he has, obstructing examination of his tax returns, will fall away. He's certain to face prosecution for tax evasion. Also, examination of his returns may very well disclose his Russian ties and obligations.
So I think that he truly wants to win a second term, to keep all of the above from happening. Yes, he's going about that in spectacularly inept fashion. But he's always been spectacularly inept, lacking the intellect to form a cohesive strategy to campaign or to govern, and lacking the human empathy and common decency to understand what people want. His hate-focused "appeal to the yahoos" strategy in 2016 just happened to work. I doubt that even he expected it to.
Also, I doubt that his ego would allow him to "lose," and we all know that his ego drives him with a bullwhip. I think that what he's doing is setting up a whine, whine, whine strategy where he can blame his November defeat on the Deep State or Fake News or a Democratic hoax or something, anything, to enable him to tell himself that he didn't really lose.
And one final thing--he's acting like a fourteen-carat jerk. But that isn't any kind of grand strategy--it's just "Trump being Trump." He literally knows no other way to behave.