Spoken Content controller: cannot move between different full-screen applications

I often use the Spoken Content accessibility feature, where I highlight text and have my computer read it to me. I almost never have any issues with having my Mac actually read the content I select, that's not the issue. The issue is, however, that the Spoken Content Controller box often gets stuck in the "main" window, even if the content that it is currently reading is from a different window/full-screen application.

An example for the sake of clarity: I like reading most things in full screen, so I click the little green button at the top left corner of my page window to expand it out, so the application has its own window all to itself. Great, no problem there. I go to that now expanded application, I highlight/select some text, and I hit the keys to activate the shortcut to begin Spoken Content, and my Mac begins reading my selected content to me. Still great, no problem there. However, at this point although my selected content (from my full-screen application) is being read aloud to me, the controller does not appear in the same window as the selected text which is being read. Instead, the controller box can only be found in the "main" window, or the original desktop window. Because of this, if I want to speed up, slow down, pause, skip forward, or skip backwards in my selected spoken content, I have to navigate away from my full-screen window over to the main/desktop window, make my adjustment there in the main/desktop window, and then navigate back to my full-screen application, from which my computer is reading. If to you that sounds incredibly inconvenient (especially for an **accessibility** feature, mind you), you're absolutely right. It is incredibly inconvenient.

Interestingly, when the computer first boots up from a restart, it doesn't have this issue. The controller will appear in the same window as the selected content that is being read. However, inevitably, the controller box will eventually stop appearing in the appropriate window and only appear in the main/desktop window, necessitating either 1. a computer restart, 2. minimizing your application back down to normal size (to make it no longer a full-screen application) so your text and your controller can be on the same screen, or 3. endure the incessant swiping/navigating back and forth between the full-screen app and the main screen pages to adjust the spoken content.

Not sure how to fix the problem, as the controller box cannot manually be moved between windows/full-screen applications. It just decides on its own which window it will appear in, and there seems to be nothing we can do except just hope it chooses to appear on the same window as the selected text (which only happens ~30-40% of the time). Once it erroneously appears on the wrong (the main/desktop) screen, it will forever more appear there and not in any other window unless the computer is rebooted. Anyone have any ideas on what can be done to fix this?