The scope of a custom menu is set within the Menu Manager utility itself - a bit like custom channel layouts.
So you can define multiple menus and show these to different roles etc. HTH 🐾
Yes, it is possible to update the “Custom” menu in the sidebar for a specific member role. If you want all “Editors” to have a link to a plugin in the sidebar, you can customize the menu settings for that role to include the desired link.