The issue you are facing is the way the stoke end is rendered. I am not aware of a way to make it end exaclty at the angle you need. None of the stoke-linecap values would fit. You should also note that the path element in your SVG doesn't have the same start and end points.
A way would be to make the path go further than you need it and hide the overflow with clipPath. This way, the sroke will end at the desired angle: