I see that you’re still wishing for Roon Server running on an RPi4. It won’t happen, and not because Roon Labs don’t want to do it or that the developers don’t know how to do it, it’s simply because Roon Server makes demands that an RPi4 (or RPi5) simply can’t meet. It’s not a straightforward digital player like Audirvana.
The definitive view of Roon Labs on making Roon Server available on other platforms was given here: