Android head unit for Audi with Bose amp to all speakers

[e-honda]

I've got an old audi S4, it has a nice Bose sound system but the head unit is basic and I am considering putting in one of these cheapish double din android head units.
The Bose system doesn't have any powered speaker outputs, you can get a harness adapter which has 4 RCA connectors and a power signal to the Bose system, I think that should be fine to plug in a stereo that isn't a top brand and still get decent quality sound as I won't be using the built in amp, but most of these cheap head units even if they say something like "full RCA output" seem to only have a left right and sub channel, I want 4/5 channels. I don't know how important having 4 channels is, I could presumably use a splitter, but at the least I would lose the ability to fade from front to back.

Does anyone have any advice or recommendations?

[markiii]

have a look at the Joying stuff

[ltj]

Buy yourself a branded stereo pioneer sony kenwood alpine jvc
Cheap androids are too unreliable and sound awful imo

I stopped selling Androids because my suppliers slashed the warranty to 30 / 60 / 90 days .