You could recreate the Share App screen yourself. All you need to do is create a sheet that contains headings for the text and the link. You can either copy the QR code image by itself or create a screenshot with just the QR code and the text below it. Then build a screen that contains the image, text, and a button that will copy the url to the clipboard. You should be able to create a tab with almost identical looks and functionality as the built in share app screen.
For your “+” Add functionality, I would just create an empty sheet with at least a heading for the first column. Add that as a new tab in your app. Then add a form button that will allow the user to add data to your app.