I just tested here and won't run in Catalina. They have perform a huge step from Mojave to Catalina... and fall with the face on the floor! They have dropped all 32 bits apps and etc, it's full 64 bits now. I am with Catalina since the beginning (usually I don't upgrade so soon) and each upgrade fix some issues and bring new flaws, you know, like Windows. However, as I can see troughs my researches and tests, soon not even Linux will support 32 bits and other old technologies, it's a matter of time, so I strongly advice you to take a deep breath and upgrade your Unity or whatever you need to support Catalina (it's not about macOS only). Unless some foundation decided to handle 32 bit support and old techs at OS level, we got no choice, is beyond our capabilities.
Thought building for Mac is hard? Don't try to iOS...