I'm sorry I'm not sure what Ruenel is referring to in the changelog either so I'll go back to your previous questions:
This thread is about the collision of the old Appearance > Customize > Typography settings using the WordPress Customierzer and the native Theme Options settings.
The Customizer has been discontinued since X 5.0 so the collision is no longer an issue at this point.
This especially does not concern new sites built starting from X 5.0. Maybe sites before that version might need to reconfigure some theme options settings.
For your question:
The Typography section or Theme Options > Typography and the Font Manager are 2 different features that can be connected. The Typography section controls the global body and heading font setup whether you'll use or enable Font Manager in it or not so that is the choice you have to make at this point.
To help you make an informed decision, if you already have decided what combination of font families you're going to use for your body and heading, you can't opt to disable or not use the Font Manager in Theme Options > Typography. If not, you can create font sets in the Font Manager and enable it in the Typography section so you can choose what you've setup. Think of it as a color pallet but just fonts.
The Font Manager allows you to use Typekit and custom fonts. If you don't use the Font Manager in Theme Options > Typography, you're only limited to system and Google fonts.
For more details about custom fonts, please see https://theme.co/changelog/#theme-pro-2-3-0-theme-x-6-3-0-cornerstone-3-3-0.
For more details about the Font Manager, please see https://theme.co/apex/forum/t/font-manager/101
Hope that helps.