The press talks a lot about the 32 bit thing in Catalina. But MUCH MORE has changed in Catalina.
In particular, you can only install "notarized" apps that have been approved by Apple. Only new apps are going to be approved. So no old apps can be installed, and being 64 bit will make no difference. Certainly, you'll need the latest CC, probably with updates after Catalina is released. Don't be on the bleeding edge!
There is no history in which old applications have been guaranteed to operate on new operating systems. In Creative Cloud, only new applications have been announced to support new operating systems. CC 2018 is a legacy application and will not officially support 10.15.