It's hard to know what actually gets investigated in the FBI versus just overlooked. This is true under both dem and pub administrations.
However, regardless of what the FBI has and has not done, it is crystal clear from the existing record that the State Department and the diplomatic corp identified and recognized Hunter Biden as a bad actor long ago - a loose cannon rolling around on the deck of the ship. And notably, I am saying even during the Obama administration. Hunter and Joe's meddling made their job infinitely harder long before the republicans started picking on him. They saw what was going on.
You will recall that George Kent the diplomat in the Ukraine testified during the impeachment scam that he had repeatedly warned his superiors in DC that Hunter was up to no good.
Further, the Ambassador, Marie Yuvanovitch, testified that the Obama administration had in fact prepared her for her confirmation hearings and the preparation included giving her talking points about how to handle predictable problematic questions about Hunter messing around there.
Aside from all the hyped up political mileage that goes with campaigns, it is ABSOLUTELY TRUE that that Joe/Hunter arrangement was/is a national security risk. Holy Shiite, you have some desperate druggy who can be had by any country anywhere that has a sixpack a few million dollars working as a go between between the country or it power elite and the Vice President/President- and the VP is taking a cut off the top of every deal and is possibly about to be elected President. Jeeeeeezuzzz H. on steroids. This is what we learn/get after impeaching a president for a conversation with the Ukraine?