Each tv needs its own Roku device.
Edited to add:
But each of them can be linked to the same Roku account and will get all the same channel apps. Any subscriptions you pay for through Roku will also be attached to the Roku account and shared to all devices linked to this account with no extra charges for multiple devices. Subscriptions you may have directly with the channel will be available on all of them whether they are linked to the same Roku account or not.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X