EQCMastiff

I have a library of around 175 k tracks that I want to use in the car, like I use it in the house, cabin and boat. But the navigation of such large libraries are cumbersome in the MBUX, especially since it can't filter in hiearchy (Genre/A-Z/Artist/Album). So I'd like to use J.River Media Center, which I also use in the house, cabin and boat, on a Pi 4. Another nicetiy with that is that I can actually get some bass in the Burmester system without doing a subwoofer mod. When I use my phone, even if the sound isn't very good over Bluetooth (USB sticks with high quality MP3's sounds much better, so I wish they had a bass adjustment that went further than what's 10 in the system), I can have enough bass for me not to miss a subwoofer mod, that would take up space too. I have seen HDMI interfaces like this:

https://incarsolution.com/en/mercede...ntg6-mbux.html

And AUX in like this:

https://www.car-interface.com/vendit...5-60-mbux.html

But I'm a bit reluctant to spend a few hundred dollars (or rather a few thousand Norwegian kroner) without knowing that it will actually work, without messing up stuff like the 360 camera, internal nav and so on. So does anybody know if this actually works on an EQC? I guess there can be differences to the models the units are built for.