I don't do much audio editing, so I cannot realy comment, But...

I have bought iZotopes RX9 Audio Editor, and that may be worth checking out.
I only use it to separate complete mixes into stems (musical balance), which is working fine. This was my sole reason to buy it.
But you have a lot more tools in there. All of those also as a PlugIn within Studio One. Only musical balance is "stand alone".

Being a Studio One user myself, I share your feeling that nothing else is needed.


“Musicians”: UltraPak 2024
DAW: StudioOne Pro 6.5
"Instruments": VSTs and REs
Notation: Notion 6
Interface: NI Komplete Audio 6
Mic: RØDE NT1-A
Controller: Panorama P6/KAWAI VPC1/Atom
OS: Win 10 64 Pro