I don't see how anything changes regarding the likelihood of success in prosecuting Biden. A new AG may think it's worth prosecuting anyway, but they would almost certainly lose. Just a waste of taxpayer money.
As much as I'd love Jack Smith to make all of the evidence and documents public, it would go against practice and also be bad for Trump. Usually, at the end of a Special Counsel investigation, they submit a report. I'm not sure how that even plays out under these circumstances.