The kingdom of Sardinia seems to have many superficial similarities with Prussia. It was arguably Italy’s Prussia at least during the mid 19th century and the Italian unification. Plus Piedmont could be Sardinia’s “Rhineland” and the term Kulturkampf has been applied to the secular elements of the Italian unification.
Meh sardinian never had that great army, Only Cavour modernize it and even then it wan't on the prussian level...
I would rather propose a surviving Visconti/sforza in Milan, they even made for a short time an union with Genoa so an idea would be to unite the 2 nations and then seizei the italian territories of savoy to have a nation protected from the alps. at that point just keep swapping alliances with france/spain (basically italy of the 2 world wars

) and take down slowly venice( and the colonies before ottomans) then just go south on Tuscany( around 1580?).
After taking tuscany Italy was technycally formed( until 1800 italy was considered only the north of the peninsula) take the iron crown from Austria and wait for the religious league to ally france/sweden and jump on the pope while spain and austria are busy in germany/netherlands. after the 30 years war the new nation lacks only southern italy and island( except corsica alredy owned ) spain is in its decaying period( no gold left from americas, no tech advance and habsburg are busy with making deformed childs from their incest marriages) so ally again france and take the south while france takes colonies or barcelona. At the end of the war italy is reunited with crimean colonies(from genoa), greeks colonies( from venice and genoa) and the Gibraltar street( from genoa, even today in OTL there is plenty of genoese surnames and one of the offical languages is genoese) and it's like almost 1700?
P.S. you may say:" wait what about the ottomans, they won't just sit there and look." you're right but i'm pretty sure that a nation that has the bot the genoese and venetian navy arsenal under single command would be pretty able to defend from the ottoman one, just know that Andre D'oria was able to do great things with he's 30 private ships ,imagine him at Lepanto with 60 or even 70 galley all under his command
as usual any correction is well accepted( both grammar and history) an thank you for reading