I have some vague memory from research I did long time ago.
As far as I remember the oem cam was/is 5v not 12v as most amazon and ebay cams are.
Also If I recall the infotainment screen resolution was limiting factor on the older Mazdas.
On the latest CX5 and cx30 there is a new higher res infotainment screen which then makes sense for Mazsa to have an oem high res camera.