The Live Corners dialog button on the Control bar is the only way to precisely adjust the radius, rounding, and corner type of multiple corners in a non-rectangular object. I see no reason why these settings shouldn’t be included in the Properties panel.

This functionality can’t even be accessed via the menu bar or a keyboard shortcut.

Keeping the top control bar open (which is no longer even activated by default in the Essentials workspace) for just that one button is a waste of space, since just about everything else displayed in the Control bar is now displayed in the Properties panel.

While you CAN double click on a Live Corner widget to bring up the full Live Corner dialog, you have to do this manually for every individual corner you want to adjust.