Mechanical Disc mount too “high”

So I’ve been riding this inexpensive Amazon bike, as a way to dip my toe into the waters and learn to fix/adjust things, than being said I’ve been very happy with it out of the box and am now onto getting it more tuned in for the spring/summer.

I’m stumped on the rear brakes, I’ve searched and a lot of more expensive brands notate the mount offset among other things, this bike does not. I know it’s a 180mm rear disc but it appears the mechanical caliper sits too high on the disc and only grabs about 1/2 the surface. I was thinking I could cut the mount down to lower the caliper onto the disc to provide more grab but figured there is probably an off the shelf mount that can be swapped.

So my question is, what is this bracket called (red line in pic) And as the offset is not noted what are you referencing to measure the offset? It almost looks like I either need a different bracket or a larger disc, or modify my bracket… I’ve seen is* bracket mentioned in some other posts similar to this but not sure if that’s what I’m looking at here.

Thanks (Yellow circle in pic is just to show how the caliper grabs high on the disc)

by Budd0413