well I don‘t know from where you got your information that only $ 10k is allowed to bring into Thailand and above has to be declared? I still rely on this piece of information:
are you sure it has to be in baht or isn‘t it enough you carry equivalent amount in any foreign currency? We never brought any baht with us and changed first time after arrival
well I did it and it was a very serious company. If you don‘t have Thaiwife or Thaifriends and every bank branch refuses even though you bring all docs needed and plus time is running out with the non O 90 days then you are grateful for any help