Help with 6C Polo head unit upgrade to RCD340G

Hi all, first time post long time stalker! This forum has helped me with issues in the past and I am hoping you might be able to do the same now.

I have a 2014 Polo TSI Comfortline (one of the first newer versions off the boat) with a factory installed reverse camera. I am trying to upgrade my current stereo unit (6C0 035 869 B) with what I thought would be a plug and play, being the 6RD 035 187B, or the RCD340G Android Auto CarPlay mirror link. Needless to say it’s not happening. We managed to find a new harness to adapt from 40 to 52 pin, and have power, but I still have two main issues:

1. The factory camera is not working - it comes out of the loom (we checked) and there’s a plug in for RCA, but I am not sure if this model is RCA or if it needs an adaptor. Any thoughts?

2. More importantly, the Can Bus is not connecting, like at all. I can’t pick up the engine at all, and this would impact on the camera working anyway I would think as it won’t engage without telling the unit that the reverse has been activated. From the pdf of the wiring diagrams I saw on this forum before I think the can bus coming out of the car is going into a different point in the harness and therefore the new unit, but I am honestly not sure.

So what I need is some advice please. I think this is a dead fish project, but can anyone give me some advice or assistance who has upgraded or worked with a stereo change in my model polo from that specific 6C unit? Have you tried putting in a 340G and have you ended up throwing the thing out the window? I’m a tech geek and have done installs of stereos from scratch before, but this one is killing me! Thank you!!! Flossymoo.