I am a heavy email user currently working with Postbox. Using their Quick Move function a lot to move emails into folders with keyboard only: https://support.postbox-inc.com/hc/en-us/articles/202200620-Quick-Move

emClient has a shortcut (cmd + shift + v) to move emails as well. But PostBox's version is much quicker with less keystrokes.

PostBox keystrokes:

• Shortcut (v) - opens quickmove box
• typing "Arch" (like in the screenshot / docs) autocompletes closest match (meaning closest match in folder structure). Below are other results - but only the matching folder, without structure
• a) Hit Enter to move mail to preselected folder
• b) move down (Arrow-Down key) to another folder and hit Enter

=> minimum of 2 keystrokes for functionality + 4 keystrokes for the search entry "Arch" => total of 6.
Additional great feature: when hitting 'v' again, the quickmove box preselects the last used folder

EmClient keystrokes:

• Shortcut (v) - opens quickmove box
• typing "Arch" (like in the screenshot / docs) filters the results view (but shows the complete folder structure)
• hit 'tab' to switch to folder structure
• multiple Arrow-Down keystrokes to navigate to result folder (depending on nested folder structure)
• Hit Enter to move mail to selected folder

=> minimum of 3 keystrokes for functionality + 4 keystrokes for the search entry "Arch". Realistically with sub folders additional 2 - X clicks for Arrow-Down navigation. In my scenario: => 10 clicks

Is it possible to adapt the quickmove box like in Postbox? If needed, I am happy to capture a video to show how fast this feature is in Postbox.

Maybe you can use a setting to let the user switch between default 'move popup box' and a new 'quick move box'.