(Talked about this plenty of times before about the HRE and Bismarck, but I want to hear other people ideas. This also may be ASB, but I wanted to talk in the Before 1900)
AHC:Have the Holy Roman Empire be revived after the Congress of Vienna, and then have the Prussian Hohenzollerns replace the Habsburg’s position as the HRE Emperor, invite Teutonic Order back to Prussia (which was still a thing) and declare unification of the New Holy German Empire in 1871
(Either name could be Holy German Empire or the German Teutonic empire, or the Empire of the German Order).
(Here's a flag I made of the new Empire)
AHC:Have the Holy Roman Empire be revived after the Congress of Vienna, and then have the Prussian Hohenzollerns replace the Habsburg’s position as the HRE Emperor, invite Teutonic Order back to Prussia (which was still a thing) and declare unification of the New Holy German Empire in 1871
(Either name could be Holy German Empire or the German Teutonic empire, or the Empire of the German Order).
(Here's a flag I made of the new Empire)