That’s not what happended.

The Supreme Court refused to prosecute Trump (for a blatantly illegal act) and ruled that he was immune to prosecution for “official acts” which they refused to define.

Then they slow walked the case back to a lower court - deliberately - so the determination was not made until after the election.

Then in a state court, Trump was convicted, but the judge delared there was no penalty “because only a federal court could apply punishment”.

Then a couple of days later the DoJ dopped the case because “the president is immune from prosecution”.