So far as I saw from following the trial (not super closely, so I may have missed something), no defense witnesses were prevented from testifying if they had relevant evidence. (You don't just get to put, say, Trump's hairstylist on the stand, unless they have something to say that touches on admissible evidence.)

The part that seems more in line with the claim by the green account was not about witnesses, but lines of argument.

There's a claim called "advice of counsel". In this case, it would be claiming that Trump's lawyers told him to do this. Well, in a criminal trial, you don't get to just claim "my lawyer told me to do it" and that's automatically a get-out-of-jail-free card. No, the prosecution gets to examine that claim. In particular, they get to put your lawyers on the stand and ask them questions, under oath, even though those questions touch on matters that would normally be covered by attorney-client confidentiality. [That is, asserting that defense leads to loss of attorney-client confidentiality in areas covered by the claim of advise of counsel.]

Trump's attorneys chose not to assert that defense. They told the judge, before the trial, that they weren't going to use that defense. Then, during the trial, they wanted to make an argument that was something like "recommendation of counsel", where it would sound to the jury like "advice of counsel", but the prosecution wouldn't get to grill the lawyers. That is, they wanted to have their cake and eat it too.

The judge didn't let them do it. Trump's lawyers tried, at least twice with different wording, and the judge blocked it. Rightly so - you don't get to skirt the restrictions by trying to re-word the label.