prosekit/extensions/gap-cursor

function defineGapCursor(): PlainExtension

Capture clicks near and arrow-key-motion past places that don’t have a normally selectable position nearby, and create a gap cursor selection for them. The cursor is drawn as an element with class ProseMirror-gapcursor.

You can either include prosekit/extensions/gap-cursor.css or add your own styles to make it visible.

See prosemirror-gapcursor for more information.