Okay second Big Blue Blob try. I tried becoming the Emperor again. I even thought I got super lucky, because I got the Papal controller very soon and Austria was rivals with the Pope for some reason. But Austria refused to die, and despite the excommunication was able to regain two electors to my two. Which means they as the Emperor win. I would have had three, but Bohemia narrowly went for another state. And I was already maxed out at 200 relations, 100 prestige, a diplo rep advisor, etc.
However the rest of the game went much better.
In my intial war with England, I had moved my navy around from to the port north of England's South France possessions. Then I got super lucky when they sent their transports alone down to their, while all the heavies blockaded the north. I not giving a shit if my navy got wrecked in exchange for hampering the English landing troops then attacked. But the AI kept it heavies blockading while I bashed up their transports. But being England they only two transports despite being a stack of transports with no leader, against a larger fleet with heavies and a admiral. They landed in the port after their defeat, when Portugal arrived which got my Southern besieging force narrowly defeated. But since I was trapping all of England's transports, I was free to put the minimum on their northern fort, while I put another seige stack on Calais and sent the rest to unite with my beaten Sourthern forces to beat up England's sole Stack in France and Portugal. Then it was simply a matter of seiging down the forts and then seiging Portugal. The Transport fleet returned to England after I took the fort, with another two ships lost, allowing England to send stacks again and take the northern fort. However I was just peacing out Portugal by that point, so I was able to return and retake the northern fort.
However there was a complication. Scotland had declared it owns war. Which was fine. Except that they had seiged the Pale, preventing me from taking it in the peace deal. Annoyed at not being able to get a Irish foothold, I instead took Man as well as all of England's mainland territory.
However Scotland's war proved a blessing for my English conquest. They got soundly beaten. England taking a bunch of provinces, forcing them to set free their vassal the Isles (which revokes their cores on them) and revoking their core on Man. No idea why they did the last thing. But it allowed me to diplo vassal Scotland, after I attacked the Isles their former vassal and annexed them. Which meant no distance penalty. Hire a diplo rep advisor (+3 to acceptance), Great Power Influence (+ Trust, which gives some acceptance) and a Royal marriage (+10) they were ready to be my subject. Then after my truce, I attacked England with my armies in Scotland, taking back their cores, their intial mission claims on the two bordering provinces and took their Irish provinces for myself. During the truce they had annexed a few of the Irish. I then finished the job with the rest of the Irish and diplo annexed Scotland. Scotland also got a event to get two of Norways North Sea islands.
The British Isles weren't my only route of expansion. I allied Castile and rivalled Aragon. My plan was in the intial war to take a province war to release Catalonia, give Castille Aragon's mountain fort to make a future war easier and take Aviagon from their ally, the Pope. Then in a second war I used the age ability to transfer Naples to be my vassal, and with the remainder of the war score fed Catalonia. I also had to give Castile another province because I accidentally called them in with a land promise. My future plan is to annex Aragon's Iberian provinces personally (Since I diplo annexed Catalonia while I was doing it with Scotland), while I fed Naples it's cores on Sicily and Malta while I annex them.
The last expansion was in France. Provence and Brittany I went to war with immediately after England. This was due to Provence, getting attacked by Burgundy, Brittany and the Pope. As the papal controller I then excommunicated them and attacked as well. Then I attacked Brittany who had seiged the province next to them, and the ones by the coast, taking those. Burgundy and then the Pope meanwhile seiged their Bar and Lorriane PU. For some reason Burgundy didn't take anything from them. The Pope meanwhile couldn't take anything because no border. So I annexed Brittany, and after those were cored, Provences non HRE provinces. I didn't take Bar or Lorriane because of AE, but I did force Provence to release Bar. Which replaced a angry Provence with a lot of AE against me, with a Bar with no AE.
Burgundy I had been leaving to try to become Emperor. But failing that, I just went after them normally. I won the war. The problem however was the event not firing. I did a third war against England while I was waiting, annexing Wales and Cornwall, since they are low dev provinces. I took a loan to get the Defender of the Faith (Ticking minus war score) to counter the growing call for peace and wasted a bunch of diplo points reducing war exhaustion. I still ended up getting 14/20 war exhaustion before the event finally fired. The excommunicated Austria got the rest.
So my plan for the last decade and a bit is to wait for my war exhaustion to tick down, while I diplo annex Naples. During that time I will kill Aragon. Then I will attack Austria. Even without Naples, that nets me enough provinces to get BBB. Without any coalitions, or expansion into the Balkans or Norway.
Anyway. Pro tip for any Catholics who have a Cardinal at the start. Use the estate interaction that immediately gives you 10 papal influence. The pope is fairly old, so you have a good chance of getting the papal controller very soon. Which is very powerful. Cheaper and more advisors, less AE, a extra diplomat which is great for getting everybody to like you more then they fear your AE, etc,
), and Poland lost a province to Muscovy.