@mbiasini
You don't really "backup" anything. When you get a new RokuTV (or an additional Roku device), just setup and activate it using the same email address you did with the Stick. (this email address is your Roku account).
When you link all your Roku devices to the same email account/Roku account, all your channels/apps are shared amongst the linked devices. If you remove or add a channel/app, you will be removing/adding that same channel/app amongst all the linked Roku devices.
https://support.roku.com/article/360000321787
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, 4802, 4850, Premiere+ 3921, Express 4k+ 3941, Streambar 9102