I can’t bind hotkeys to additional mouse buttons.
(Additional being Mouse 4, 5 etc., button codes after left, right and middle click).
Navigate back and Navigate forward are apparently already bound to Mouse 4/5 (which seems to have been an issue), the same way its done in browsers and IDEs I know, but this is not noted in the hotkey settings and trying to bind anything to these keys just navigates notes in the background.