Were there any attempts at a federation or commonwealth to save Austria-Hungary from breaking up after ww1?

Question

As known, the population of Austria-Hungary was made up of 11 major ethnic identities.. When the war ended, A-H broke up as it was instead of forming a new federation of Austria, Hungary with an exclave in Romania, Slovakia, Czechia, Bosnia, Croatia, Slovenia with land ceded to Italy, Sudantenland to Germany, part of Galicia to Poland and another part to Ukraine. Also major part of Transylvania to Romania.

At least Hungary would not feel bitter about the Treaty of Trianon through which Hungary lost lands.

Were there, in fact, any attempts to create such a federation after World War I?

(FWIW, Poland, Lithuania and Ukraine could form another commonwealth on their own (PLU). With an access to the Baltic Sea through Lithuania, the importance of Danzig to this PLU would be diminished. There would be less pretexts for the N-Germany later on to intervene and invade lands outside of Germany.)

Answer 1

There were some attempts for that. To start with, Austro-Hungarian Monarchy was also a kind of a federation of two member states, Austria and Hungary, such that foreign policy and defense was under the control of the emperor.

1. In the last weeks/days of his reign, Charles I of Austria (Charles IV of Hungary) wanted to do a reform on the Austro-Hungarian monarchy. He at least wanted to give Croatia (which officially was an autonomous part of Hungary) a status of a member state, i.e. for it to become equal with Austria and Hungary in order to save the monarchy.

2. Oszkár Jászi negotiated with all nationalities of Hungary in 1918. His aim was to create a federal state with one member state for each nationality; this would have been the ''Danube confederation''. He also proposed a Hungarian-Romanian personal union and a joint control over Transylvania (the area which is inhabitated by both Romanians and Hungarians)

All these attempts were eventually unsuccessful, as Serbs wanted Croatians to join the state which later became Yugoslavia, Romania wanted to take control over whole Transylvania, not just the parts which were inhabitated by Romanians, and Czechs and Slovaks wanted to establish Czechoslovakia, again by getting control over large lands not inhabitated by either Czechs or Slovaks (Sudetenland, Csallóköz,...).