I tested the toolbar example https://demos.telerik.com/kendo-ui/toolbar/keyboard-navigation with a keyboard and screen reader (NVDA) and found the following issues:
1. Buttons are rendered as links. The SR announces the first button as "Button visited link". Apparently, there is an undocumented option useButtonTag (https://github.com/telerik/kendo-ui-core/issues/4730) that's also missing from the typings. I have to manually add 'role: "button"' to every single button to make my toolbar compliant.
2. Toggle buttons state is not announced.
3. The overflow menu button has no caption and is announced by the SR as "blank".
4. The overflow menu button has no visible focus styling (screenshot attached).
5. Selecting an item from the overflow menu throws the focus out of the page.