And that’s a big IF, and the answer is “no.” Google isn’t setting any new requirements for something running on “Android.” They are adding new APIs (and deprecating old APIs) in new releases of Android, and they are changing what user-installed software is able to do in newer versions (some things that could be done by user applications previously now are disallowed… for security reasons, as Google puts it). They also make it so some things must be built against reasonably recent SDK version to be allowed to run on the latest Android version. This is applicable for something like Roon, which needs to run on the multitude of currently available non-dedicated user devices. At some point they look at how many different ways they have to do the same thing, depending on the Android version, and whether supporting an older version will even allow Roon client to run on the most recent version of Android.
This is all fine and well and makes sense when you are targeting user devices in the wild. But it hjas absolutely nothing to do with Rose’s situation, where HiFi Rose controls both the OS and any application you can install on it. There is no way for Google say that “oh, and RoseTube now won’t work on RoseOS.” That’s not how it works.
The only reasons why the Android version in RoseOS would have to be updated would be either if there were some glaring security flaw found in the current version, which could not be patched, or if the SDKs Rose uses to integrate with external services were deprecated, and newer versions were to require a newer Android version. Could that happen? Sure. Is it going to happen in some near future? Quite unlikely.