This is why I will never use rock on their server or on mine.
IMO, it’s foolish to take all of the Linux diagnostics out of the OS like rock did to save a couple cycles, and that’s why nobody will never know what is causing any problem you have.
If I’m wrong, can you tell me how much cpu usage % while running? Are you swapping/paging? How much of the mEmory are you using? Any disk/ssd errors? Ethernet/network errors? I have close to 4TB of music on my server.
I’m using Mint Linux for Roon and I have hundreds of diagnostic commands and tools to see exactly what is going on in the OS. I’ve ran Roon on OSX for years and I also had many diagnostic tools/commands to diagnose any problem I might have.
The OP and many others for years have reported problems they were having and most posters indicate that they think upgrading to the bigger server is what needed. This could be a foolish move because you don’t know what is causing the problem.