If it has balanced xlr inputs a DI will completely eliminate the earth hum. That the signal is dropped to mic level doesn’t matter much as the impedance is correct, the connection balanced and the mixer preamp designed for the purpose. // I am somewhat professional sound tech :)

Be fun to program them but I can’t find any programmable devboards with the Capstone CS5213.

Not much information out there but these are similar chips, possibly it’s a clone?

Capstone CS5213 datasheet:

https://file.elecfans.com/web2/M00/2B/BD/pYYBAGHVUbyARd_-AAU...

And also the AlgolTek AG6200 / AG6201 Series, datasheet:

https://assets.yoreparo.com/attachments/28SGHqLW2Z2MfSzEBJB4...