Chiming in a bit late, but:
Definitely check out Scheduled Refresh if you have not already. This is essential if you're using Import Mode in your Power BI report.
If you're using a Power BI report, you might want to check out Automatic Page Refresh - it's quite handy for this sort of thing. However, it has some limitations that you'll need to be aware of. For instance, if you only have Power BI Pro, you can't get your page to refresh more than every 30 minutes at most. Be warned, this does NOT work with Import Mode. Also, Automatic Page Refresh does not have any sort of tab rotation/slideshow mode.
This is also a Windows 10 Power BI app in the Microsoft Store. It's OK, but it's quite limited in functionality.
I've actually built a custom Power BI app to help you build slideshows from Power BI reports and dashboards and display them on TVs, it's called Displagent. You can also find its docsite here. It has a lot of advanced features, much more advanced than the Windows 10 app from the Microsoft Store and Automatic Page Refresh, so check it out if intersted, happy to give you further info!
