I don't like it, but I'm pretty sure that's how it'll shake out.
Non disclosure agreements are legal. Done all the time. The story had been out for years and effect on election already factored in. Even if it were to enhance image for election rather than to protect Melania from pain as Cohen testified that is not illegal. The whole case is bogus for many add’l reasons.
The immunity decision just gives the case one more blow since presidential conversations were illegally entered into the court testimony.
But the payments began after Trump became President. The supposed illegal bit was that the hush money was to affect the outcome of the election. But no money was paid out prior to the election, so no hush money, so no illegality. This whole thing was a sham. It doesn't matter if it was personal or official, no illegal act happened.