Big Sur Cycle through windows-Command

Hi there, as Big Sur dropped support to cycle windows for some apps (Window menu), it would be nice to be able to do this with bettertouchtool.

Example: Finder and Terminal still let you cycle through windows using a keyboard-shortcut.
Mail.app does not let you cycle through windows.

There already is an action in bettertouchtool to display the window-list of the current app.
This can be navigated using Keystrokes. But this is very cumbersum since switching to the next or previous windows takes three steps: Opening the window-list, using up/down-arrow and enter to finally select the window.

I would like to switch to previous or next window with one keystroke as is possible in Finder and Terminal.

Regards,
Daft