Trump has the right to proclaim his innocence as loud and as long as he wants to.
He is 100% free to criticize the prosecution's case, and the witnesses against him.
He cannot intimidate or coerce a juror. No one can do that, whether they are a party to the case or not. That's a crime, and should be charged when it happens.
The prosecutor's office cannot discuss the case in the public sphere because that is a violation of the rules of procedure and can taint the jury. That prohibition does not apply to the defendant.
The leftist media opines on Trump's guilt on a daily basis. Trump has every right to counter those opinions, and criticize the people who publish them.