Just for the sake of conversation, let's say Hunter Biden was taking money in exchange for providing services of limited value because they're way outside of his skillset. That's the surface of the investigation. The next step is to identify an actionable crime that came from it. The reason no one ever prosecuted Jared K. for his Saudi relationship is that even if he was influenced, he never committed a crime. With Hunter, people have to identify the crime. What was paid for with the money and how was it illegal. Not just questionable or shady but outright illegal.
The issue with equating this with DJT is that DJT is involved in actual crimes, not just shady actions. Campaign finance violations, corporate reporting violations, mishandling of classified documents. These are crimes, not just improprieties.
It's like equating a guy you have on tape robbing a bank with a guy who is taking the bank manager out to dinner so he can get a better loan. The second one might be unethical but only the first one is definitely criminal. Trump's actions are criminal. The Hunter stuff, so far, is possibly unethical and the ethical violations haven't even been proven, let alone the crime that would lead to arrests, indictments, etc. Equating the 2, unethical vs. illegal, is foolish.