Maybe so. But legal experts who are smarter than you or I have stated that this case is different, because the charges came AFTER he had left office as POTUS. And if a conviction comes DURING a presidency, then it is unclear because nothing addresses this scenario. So it is untested.
I'm not arguing that it should happen.....i'm simply saying that someone saying it "cannot happen" isn't correct.
He's innocent until proven guilty. Even if he's convicted no doubt it will be appealed and probably all the way to the Supreme Court. Chances then are likely the entire case is dismissed because Constitutionally the only way to hold a sitting President liable for "high crimes and misdemeanors" while he is in Office is to impeach him. Previous court proceedings prior to his election do not bind him once he's elected.
My own opinion is he isn't convicted of anything representing criminal behavior so the entire question is a moot point.