Swapping windows in split-screen mode

I am running Android 12 on a Realme 8 5G phone. I would like to ask, how do I swap the above window with the below in split-screen mode? For instance, I may have an app I am typing into above and music from YouTube below, and I want to switch the app I am typing in without stopping the music. But when I hit the three-line apps button, it is the window below (YouTube) that is minimized, and the music stops. Instead, I want to be able to swap above and below, so that YouTube goes at the top and the app I am typing into (e.g. Google Keep) goes below, so that I am able to hit the square button and bring up Google Chrome after navigating to the Google Chrome app icon on the navigation screen where it is fine, for instance. I could have opened YouTube first and then selected split window to open Keep or Chrome after that, but in general, navigation flow can require apps to be opened up in any order. So, I would rather be able to swap the app at the top with the one at the bottom in multi window, to achieve my end. One possible way this could be done is to press the three-dot divider, drag, and then click on one of the app icons on either the top or bottom part of the screen before they disappear after the three-dot divider is released, but this does not work. How can I swap the top and bottom windows in split-screen mode?