My 2013 Mazda 3, with the Skyactiv 2.0L also has a very slight whine when driving. It’s pretty much always had it since I bought it at 40,000 miles, (Currently at 209,000) It hasn’t stopped running yet. I notice it’s a bit louder when it’s cold and as the car warms up it gets much quieter.
I’m not sure how “affiliated” they are, but https://store.awrracing.com/ make good motor mounts. I have used them on 2 Mazdas I’ve owned.
I loved my 2004 Mazda 6 Wagon.
Mine had the 3.0L double overhead cam V6 with plenty of power. (Originally developed by Porsche, before Ford bought the tech and used it in Jaguars and Mazdas.) Great suspension setup all around and a comfortable ride. With the rear seats folded I was able to transport a Ton of stuff for my new house, including a large garbage can, a pressure washer, multiple lawn tools, etc… Overall it was a pretty sweet car. The downsides were the faulty PCV valve that failed causing the engine to consume most of its oil and spin a cam bearing, and the fact that getting to the rear spark plugs required removing the intake manifold, which wasn’t really all that difficult.
Mine had also been owned by a smoker, so it got a LOT of cleaning and a new headliner to get the smell out.
Is that the line of the paint protection film?