As I said, Roon software is downloaded directly from Roon side and put in place. There is nothing DietPi specific on this. Even DietPi is not changing anything on the Roon software. Means, as well the update function is done/provided by Roon software.
Download_Install 'https://download.roonlabs.com/builds/RoonServer_linuxx64.tar.bz2' $G_FP_DIETPI_USERDATA
mv $G_FP_DIETPI_USERDATA/RoonServer $G_FP_DIETPI_USERDATA/roonserver
Next to that DietPi is not an own operation system or destro. DietPi is a set on scripts on top of a normal Debian. As well a comparison between Win, Mac and Linux doesn’t really fit. These are totally different OS system, platforms. Even between Linux bases systems you will have quite some differences.