What if Bismarck and Prinz Eugen appeared in the present immediately after sinking Hood?
Short answerThey would be militarily outclassed almost at once, and the main challenge would become securing the ships and handling their crews.
NotesThe scenario presents both a military and a human problem. Bismarck's armour and heavy guns remain dangerous at close range, but neither ship can find, defend against, or reliably engage modern forces on equal terms. Authorities would try to establish contact through modern Germany and secure a surrender before using overwhelming force. They would then face the legal and political work of handling crews containing committed Nazis alongside sailors whose relationships to the regime were more complicated.