Sonar is a great package, but my question is what do you need that RB does not do?

Are you missing some feature, or process? If you are at the limit with RB, maybe, but if you have not tapped all that RB can do, then wait and see.

Mastering is a deep subject, and can be done in just about any DAW if you have the knowledge, skills and tools. RB can do it, just as Sonar can, but you have to know what and how. Just buying Sonar will not give you or I that skill set. Do a lot of research, and see what it is you think you need, and discuss it here.

HP Win 11 12 gig ram, Mac mini Sonoma with 16 gig of ram, BiaB 2025, Realband, Reaper 7, Harrison Mixbus 9 32c , Melodyne 5 editor, Presonus Audiobox 1818VSL, Presonus control app.