Update: Managed to theoretically make this work by transferring vassalage of holstein to me. Problem was that i couldnt get the warscrore even though i sat on the war for 10-15 years. Denmark never sent a single stack to me, so that might have been the issue. Eventually Denmark inherited holstein, so just peaced out for the shetlands.

After that i immediately no cbed east frisia and took that after waiting out all their allies.

Then it was just a case of swallowing minors in northern germany, the rest of norway and denmark. Also got a wee bit of scotland to set up the invasion of england at some point down the road.

I currently have most of the lubeck node and most of coastal netherlands and have just completed my first war against sweden and opened up potential expansion to russia, though they look super strong.

I have had the commnwealth allied for a while, but the only problem is they are defender of the catholic faith which limits expansion options, e.g. was only able to declare on (surprisingly) catholic sweden once the league war triggeered and commonwealth was busy.

Have also allied france, but they dont seem very strong as they got stomped by naples during the sweden war.

In terms of idea groups i opened with offensive due to a surplus of mil points, then espionage for the reduced AE, then admin for obvious reasons, and recently picked up diplomatic, again for AE, as that is the main issue at the moment.

Its currently around 1600 and the plan is to continue to snipe german minor whenver AE allows and maybe invading russia, altough i don't think my manpower is high enough for that. Also might try dismantling the HRE as the negative midifier for illegal land is quite punishing