Thanks for your first post in the Roku Community!
We understand that you are inquiring about if you can view your Apple TV subscription on one or two devices, is that correct?
Please be advised that channel providers may limit the number of devices that can be activated. Check with the channel provider for specific limits.
We recommend contacting Apple TV directly to follow up for more help. They’ll be able to best assist with any issues and functionality inquiries. Many channels on Roku are developed and maintained by the channel provider themselves.
You can reach them here: Apple TV Support
Hope you'll find this info useful. Let us know in case you've still got any questions.