Ha! Figured it out. I was running the sim in windowed mode rather than full screen mode. Habit. I did that with FSX because in FSX if you are in full screen mode you can't drag popup panels off the main monitor to your second monitor. So I did the same with this FS2020. For whatever reason, after the installation of patch 2, the window was no longer maximized. I didn't notice that because it was still taking up the entire screen. When I maximized the window, all the missing buttons on the bottom popped back into existence. They were there all along, just off screen. Well, almost off screen. If I went back to "not maximized" I could just barely see the tops of the buttons.
Then I wondered: Can I bring the map window to my second monitor in this sim, while in full screen mode? Can't drag it there, that's still true, but the little button with the 45 degree pointing arrow - that sends it to the second monitor. Even in full screen mode. What a dummy I am! So it's back to full screen mode.