For what it's worth, the 64 bit client works just fine on Catalina without any additional supporting files. The problem is that the Launcher does not work. It is still 32-bits only and cannot be executed in wine on Catalina.

I copied all the supporting files over from my old machine to my 16" MBP, allowed "Terminal" to launch unverified files in the System Prefs, and was able to launch the client and play the game quite well using a slightly modified version of the OS X Launcher script I posted in another thread.

It's not a sustainable proposition however. As soon as the game needs an update, I would have to go back to my old machine, update it, and copy all the files over again.

SSG -you are close... if you can create a 64-bit launcher (don't forget to grab the 64-bit Awesonium binary), you will have a functional Mac client again.