I have just run into this exact issue, it was my first attempt to upload a beta channel for testing and I'm blocked.
I opened up a ticket with Roku Partner Success. I recommend you open one as well. The first response I got was that it is "by design". I don't think Roku folks realize how disruptive this is to the screensaver ecosystem. Basically, you cannot offer any options that allow users to customize settings for a screensaver and have your screensaver be a certified application. I like the fact that with the new rule in place, apps don't randomly open up the keyboard with remote key interaction in screensaver mode but a broad brush of disallowing any keyboard input just goes overboard. I am blocked as well.
I also have a ticket open. I don't think they've thought this through. I wonder when they're going to remove the Roku 4k Screensaver, as it has configuration options that the user has to select.
They're going to have to start deleting some documentation I guess.
https://developer.roku.com/docs/developer-program/media-playback/screensavers.md#settings
