@GW Buist - This is not something you can change. I was looking for some old posts as the angular connection line did not used to have such a rounded corner, however, I also do not recall it every being a hard right angle. I found this post from two years ago where the corners are a little less round:

https://community.miro.com/ideas/grouped-angled-connection-line-management-8943

The GIF from the post:

If you would like the ability to be change the corner radius, I’d recommend adding this as an Idea in the Wish List category by following the guidelines here: Wish List: Everything You Need to Know.

If you do create a Wish List Idea post, I would also recommend that you post a link to it back here, so that future readers of this post can quickly get to and vote for your Idea.