I too have a similar issue on my MBP 2020 13" i5 2.0 GHz. It's usually a flicker in the bottom half of the screen, but sometimes the entire screen appears to "blink" for a fraction of a second. It's quite random, though it tends to happen more frequently if apps like Safari, Chrome, Terminal are running.
I have installed Windows 10 via Boot Camp and it NEVER flickers there, so I'm guessing this is a GPU driver bug that will be fixed soon in a forthcoming update.