There's also the last option to allow Fidelizer to optimize your player; FB2K, in my case. Is there a particular file or component of FB I should look for to select? I typed in 'Foobar2000', and it says program not found.
You have to find the exact folder location of the .exe file of your music app, e.g. roon.exe, then select that file.
You need to know the folder in advance, which you can typically do by properties of the shortcut to your music app.
Once you've done this once, fidelizer defaults to that folder location the next time.