Hey Ben, good questions! I’ll try to answer everything one by one.
Diagonal edges will basically always be jagged as it’s cutting halfway through pixels. The only solution here is to either force the edges to be straight (causing stretching) or increase the resolution of the texture. One thing that will make it less obvious though is increasing the amount of segments of your bevel to something like 5 or 7, since right now it is razor sharp.
The gradient along the faces is from the high poly. The edges that are seams and bevels need to be marked sharp as well (I double checked the file and that does fix it), otherwise the bevel is going to cause the angle between edges to be lower than the auto-smooth threshold.
Other than that it looks like you’re spot on. Keep up the good work!
