Redraw() not working? How do I force draw?

I’m using Processing 3.5.4 in Android mode. I’ve an app where a routine is triggered by a mouse press. It takes a while to process. During the routine I want to draw some text information.
My understanding, I can use redraw() to force screen update. Unfortunately, it didn’t work for me. Is that related to this?

I couldn’t get Processing 4 working on my PC. Is there another way?

Android mode on Processing 4 is unavailable; you need to use 3.5.4 as you are doing. One alternative is Android Studio but in my experience is not as easy to use; but it does work.