I bought Youtube Premium to take-out the ads, but it doesn't with Roku, but it does with Firestick??
You need to contact Google and ask them why. If you're paying for Premium, it shouldn't matter one bit what platform is being used. I would doubt that would be legal under US law.
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee, just another user.