I think you’re missing the point. Ousting Shokin wasn’t Biden blocking corruption investigations, it was him literally doing the bidding of the Obama administration, and was supported by the IMF and the entire G-7. That’s why he was proud of it, because it was an example of him doing his job exceptionally well. Also Shokin liked to open investigations then leave them open as blackmail, which is exactly what he did to Burisma, so this isn’t some smoking gun.