Re: app.getObject('KPI1,'JGYjzsh') works, but is a complete sheet possible?
No you can't. app.getObject only works for visualizations, and sheets are not visualizations in Qlik Sense. You would need to get sheet data, which includes an array of included visualizations, and then show each visualization with getObject. This is what single does.
An easier option would be to use an iframe, and include single in it.
Hope this helps
Erik Wetterberg https://extendingqlik.upper88.com/