In the past few years I have been looking into Pre Amp's and am myself going to have a Balanced Design Produced to work with my Monoblock Power Amp's that are to be reconfigured to be a Balanced Design.
The Volume Control that has been researched by myself and one that is very well received when reading up on the reviews is the Muses.
As as you have requested a Chip, I think this might be in keeping with your inquiry, so I will propose the Muses VC for you to look at.
This VC Design has been used in a few Brands TOTL Pre Amp's.
The Link is not the only supplier, there are a few different Sources.
I believe it can have a Balance Control on the Same Rotary Control for VC.
In my mind, VC and Balance Control would be quite an interesting additional option for a Balanced Pre Amp'.
https://www.academyaudio.com/vcu