New Bracket Symbol in Leland or Edwin

I assume you are adding this as text then trying to set a large font size? That indeed won't look like what you want here - you want a symbol that is much taller than a standard bracket but no thicker. That's not something the font itself would normally provide; it's something more you scale in graphics. Like for instance, add a standard bracket, take a snapshot using the image capture tool, then add that and scale it vertically only (or primarily, anyhow).

I could imagine someday Unicode or SMuFL being extended to define brackets of different heights, and then of course our fonts could include these symbols. But you'd still need to position them separately, so I'm not sure that's any better than using an image.