It makes sense; Crackhead is the primary bagman for the Biden Crime Syndicate.
He willingly took on the job.
Of course Joe was getting a big cut. Hunter had very little cash-making ability unless Joe Biden gave Hunter the green-light to monetize access to himself. There is absolutely no scenario where Joe wasn't involved in this. Plus there was the Biden track record of monetizing his office via brothers James, Frank and sister Valerie...established before Hunter's schemes ever got going.