The new UI has changed access to add component and add variant. The add component creates cognitive dissonance, however add variant is a massive degradation in UX.
Adding a component was available via the toolbar and easy to find.
Now to add a component you must use the context menu, main menu (under object) or keyboard shortcut. Previously it was easy to find, now you have to go searching, though not a huge problem.
Adding a variant was also very accessible via the same toolbar.
To add a variant, you must use the context menu with 23 items. Find the 17th item, click on it to open the submenu, choose the second option. There is no short cut, it is not available via the menu, and it is not available via the actions on the toolbar.
While the new UI may bring joy from a aesthetics pov, and does make some items more accessible. It is a pain in the rear when it comes to components.
Maybe take a page from Microsoft and have contextual toolbars, so that when a frame is selected you can easily convert it to a component. Or when you have a component selected, you can easily add a variant. Right now it sucks, and makes me more prone to considering alternative solutions.
I cannot find the appropriate place to provide feedback on the changes to the UI. Personally I’m more of a ¯_(ツ)_/¯ when it comes to general opinion on the aesthetic changes. But reduction in usability really gets up my nose.