Hyundai already announced a two to three month delay on this plant after this whole thing. They aren't walking away, but this isn't an event they are forgetting.
It won't matter what President comes after this one, this whole thing is going to influence investment from South Korea for some time.
Doubtful that the claims will prevail. However, the filing court in Orlando is one of the courts he has out there that are packed Trump judges. Out of the 12 that sit the bench, 6 are Trump appointments. That said, even with those six in his pocket, it won't be enough to push through the claim in appeals, if it even gets that far. The Appeals for the Eleventh Circuit is the same court that struck down plenty of Florida's Online laws as violating the first amendment.
Even though they are mostly Trump appointments, the court even with them, has had a strong lean to tell the Government when it comes to speech to fuck off. Which also Cartwright which told University of Central Florida their anti-harassment policy went overboard and violated the first amendment.
Do they've demonstrated that there's very little that rises outside of protected speech. Be it a Floridian law banning children online or students yelling slurs. It's definitely a double edge sword, but I can't see this court siding with Trump on this. Defamation for this court has to directly turn into absolute loss, so Trump would have the onus to bring receipts on how it harmed him, which I highly doubt.
But all of this is a great reason why the US Government needs to implement Federal anti-SLAPP protections.