Took the plunge...and still waiting.

[Solver]

After hearing about many success stories, I finally took the plunge and updated to the full macOS Catalina Beta from the latest Mojave macOS on a rarely used late 2012 Mac mini.
It took about two hours to download, install and reboot, before the Catalina setup screens appeared.
Now the screen’s been stuck, with constant drive activity, no option to move forward, or back, for nearly a day.
Last thing I did was click “Setup Latter” in the Screen Time window below.

 

[Solver]

Nothing has changed and the hard drive is still chugging away.

 

[BarrettF77]

Power off and back on. Did the same thing. It moves forward after that.

 

[Solver]

Power off and back on. Did the same thing. It moves forward after that.

Thanks! I pressed the power button for a couple seconds and the computer went to sleep. I pressed the power button again and a login screen came up, with no shut down options. I logged in, and the exact same screen above reoccurred.
Next time I pressed the power button for six seconds and the whole computer shut down. I press the power button again, the computer booted up and loaded Catalina beta 6, and is running normally, except excruciatingly slow, currently.