About the hotkey shortcut, it have to be hard coded in manifest.json, it is the rule of webExtension so I think it'll not be easy to make an option to customize it. Chrome extension already have the built-in hotkey modifier (For example https://www.howtogeek.com/127162/how-to-create-custom-keyboard-shortcuts-for-browser-actions-and-extensions-in-google-chrome/) so we might have to wait for firefox to add this feature.