What DSP quality means would depend on the function discussed. EQuing and compressing each have their own DSP challenges.

In around 2010 a sound engineer that helped me a little bit with my album assessed the Linux EQ plugins and found most of them to be unusable due to them generating noisy artifacts. He did single out a couple of plugins which seemed to do the job well. If I remember correctly, it was this one. Unfortunately, I have noticed this myself when producing ambient. Using Zyn EQ, for example, would generate a light hiss that I had to later clean out after render.

But obviously, experts should look into this, and I think this conversation could be useful.