I totally agree with your statement. Every activity when reading or writing data tries to use the CPU with a high prioritization. Roon adds a lot of electrical noise. Roon increases the latencies. But there is a solution: HQPlayer.
I use Roon on a NAS (Server) where my music files are also located. Because Roon has the best user interface for me. On the other side HQPlayer has much better algorithms and runs on a fanless audio PC.
I wrote something about it here:
Audio PC & Control PC
I agree that Roon has better user interface and many audiophiles are willing to compromise having sound quality dropped down for better user experience. If you use HQPlayer with its own remote app (that actually work as remote without affecting audio signal mixing non-audio information from network into packets), it will sound significantly better than Roon + HQPlayer.
But changing from Roon to something like this? Some audiophiles couldn't accept that and may already bought Roon's lifetime license when it still sounded better like in early 1.8 builds.
There's always effect to digital audio in every chain even if you isolate Roon core in different computer. Upgrading computer for better sound quality in Roon core like LPS and network cable are enough proof about it.
I also share similar fate since Roon 1.8 started to sound more acceptable to me and I tried my best to optimize Roon to reach to acceptable sound performance and enjoy better user experience. It wasn't as good as my usual reference platform but close enough for better UI.
However, it got worse in 2.0 and I tried to compromise with Roon even with isolating to separated endpoint device in my system. But after 2.0 build 1202, that was the last straw. CarPlay ruined everything and RAAT from transport is the culprit. Even sending to endpoint or use HQPlayer won't fix it. A lot of my friends complained about it it and Roon's stance is "bits are bits".
Fortunately, my friend's company JPLAY has launched JPLAY app and its user experience is pretty close to Roon but offers much better sound quality that I can also use with my reference platform too. I will never go back to Roon that does everything wrong with computer audio again, ever.