I made this map taking ethnic populations, religious populations, claims, history, and personal opinions. I made this out of boredom, but feel free to leave comments or ask questions.
Notes: Bavaria is technically owned by Austria, but is autonomous. Same with Hungary. The Romanian-Hungarian border should be the WW2 one, but I was too lazy to change it. The country in Western Poland is Prussia. The country in between Arabia and Turkey is Kurdistan. Israel is both Christian and Jewish now. (Jerusalem) Austria is so big because there are so many ethnicity in the region, that I just grouped them under Austria rather than have a bunch of small, inefficient nations. Every nation is under some form of Monarchy, since those are the most efficient imho. Any nation that doesn't already have a historical dynasty is just given a new, nationalist one like the Karađorđević dynasty in Serbia or the Bonapartes in France.