Sorry about your bad experience. I don’t think US authorities are going to help you with EU 261/2004 claims. Perhaps try the German mediator at
https://soep-online.de/welcome.html. If Condor doesn’t respond to your complaint. I was downgraded on a revenue ticket and didn’t have problems getting EU prescribed compensation from them.
The takeaways are (1) both AS and Aeroplan had great representatives, (2) Condor has no (zero/zilch/nada) customer service, (3) Condor has no plan, ability, or desire to rebook onto other airlines, so don't plan on service like if you had booked with AA, BA, Cathay, JAL, or the rest of the AS MP Partners,
imagine you had been booked on BA on AS award tickets and the BA flight had been cancelled. What are the chances BA would have booked you on a non-partner airline like LH? They would have had to buy you revenue tickets. I have no personal experience with that but from recalling other FT threads it seems unlikely they would do that.