The shorthand “>>” inside the text of a note will filter the notes displayed in the drop-down based on what you are typing after the “>>”. It does not work if you put the “>>” in front of already existing text. If you want to change normal text to a link, highlight the text, and then press Cmd+K on the keyboard, or use the “Add link” function in the toolbar showing up over the highlighted text on iOS.
Furthermore, you can not link to folders or tags directly, that needs a workaround with the help of the app “Shortcuts”, as described in another thread in this forum.
About making the Home-note top level: You can create a shortcut with the “Shortcut” App which will open the Home-note directly, and place that on your home screen as an icon or even on your lock screen, as one of the two function “buttons” in the lower right and lower left corner (where Camera and Flashlight are sitting usually). But you can not make a note more top level than pinning it in the Notes folder, I am afraid.