Delighted to hear that arrowheads are coming soon. To trial Designer I tried replicating a schematic diagram that I originally produced in AI. I found the icons to be significantly quicker & easier to draw in Designer, but then came completely unstuck with the arrows.
I downloaded the post #16 brushes and tried my own post #20 pressure profile. However, with each, I ended up with variable size arrow heads & spent so long tweaking to try to get them uniform that pasting in triangles individually would have been quicker.
If there’s a beta with arrowheads available, I’d love to join it. For me also, rapidly deployable arrowheads on curves are essential.