I have roku and a ton of apps. I get ustvgo.tv and pluto.tv beautifully on my tablets. But I would love the content and Choice on my main TV.
How if it is possible
They simply might not be available through Roku..unless processed through that media browser server thing—which sounds like a connected computer. And that is a service-specific thing.
I don’t use Roku....so I cannot help beyond that.
That said, have you considered mirroring your laptop to your TV. It “might” be possible through a Bluetooth or source connection. I can do it with my laptop...but the quality is not great.
It is, of course, a whole other balywick that might require some hands on.