It makes perfect sense. But ROCK is not the best choice because it is very specifically targeted at a certain hardware configuration - likely the same issue as you had with the original OS.
Dietpi is a good choice because it is based on Debian Linux and has good hardware support but has a set of interactive scripts which make configuration and the install of the many common software components (including Roon Server) very easy.
However, anything that can be done on DietPi can also be done on any number of other linux distributions (although some have had issues on Ubuntu that needed help to resolve).
For instruction on installing dietpi on your system, see:
You will need to scroll the first set of tabs to the right and select ‘Native PC’ rather than ‘Raspberry Pi and other SBCs’.
And then you will need to select the instruction for your boot method - most likely using UEFI boot and thus requiring ‘UEFI Installer Image’
e.g:
You will need to download the dietpi boot image from the download page ( making sure that you select the correct image as detailed in the installation instructions) at:
Both pages I have linked in this post are linked to by the DietPi home page linked above by @anon37652117.