My quick take:
Look it up. I never liked the idea of this prosecution. I thought it was ill-advised for various reasons, although I conceded that the legal theory was tighter than I imagined when the indictment was first issued.
But the process was small-f fair, in that it was the process any criminal defendant gets. If you don't like that a prospective jury pool is liberal in NYC, well, then change your HQ to Palm Beach. Capital F "Fair" in a global sense? Well, sure. Argue about that all you want.
In my experience I have never seen anyone prosecuted on gun possession charges for failing to disclose a drug addiction. Hunter Biden is being prosecuted for that. Sometimes who you are matters in a decision whether or not to prosecute.