Guys, I accidentally but happily took a screenshot of my phone. And I believe in the need to share this. Coming from OnePlus to Samsung, one of the features I missed was the quick 3- prong finger scrolling down the screen and viola, you've what you need.
Well, today I sort of found something close to that. If you have ever wiped water (or any liquid) of a surface with your hand, just do same on your Samsung 21 (ultra, in my case) but DIAGONALLY top to bottom, any side works.
Does not seem to work when the keyboard is active on screen (of course, and some apps for security reasons).