I want more audiopassthrough selection

[darwindesign]

What your asking for already exists. Have you read through this guide…

Audio hardware and software configuration

This wiki article should cover all your general questions about how to connect up your OSMC device to get the best audio possible. There’s also a section with explanations of some of Kodi’s audio settings as well as information about the audio capabilities of our OSMC devices. Supported devices OSMC supports a range of devices: All Raspberry Pis and our own Vero series (Vero 1, Vero 2, Vero 4K, Vero 4K + and Vero V). Veros have an HDMI port for video and audio, a 3.5mm port for analogue au…

It sounds like what settings you need is to set channels to 2.0 and enable passthrough for AC3 and DTS and enable AC3 transcoding. With the options for eAC3 and the other newer formats not enabled you should get only regular AC3 and DTS core output.