As suggested already by @PerryJohnson the JavaFX library also has to be installed first in Processing 4.3 and it must also be imported:
This is also something that impacted me:
Let me know if it is the same with you.
The libraries are installed I could just not see them checked in the Libraries Status field without Android mode installed!
At the top of the Processing IDE you will see a Sketch tab and that will show the installed libraries that can be imported.
Sketch > Import Library… > List of libraries that you have installed that you can import!
Have fun!
:)