I am thinking that a sweet tomato heel with four wedges (instead of the usual three) would produce a sharper angle. You can work as few or as many wedges as you like.
The only thing would be whether the turn would happen fast enough, or in a short enough number of rows, if you know what I mean.
The advantage of a ST heel compared to a standard short-row heel is that it creates a more rounded shape.
Here is a Ravelry project that shows the shape:
https://www.ravelry.com/projects/Ladyebug/cats-sweet-tomato-heel-socks
(Sorry if you don’t have a Ravelry account, but I couldn’t find a photo elsewhere that illustrated it well.)
I think that when stuffed this could look rather like a knee.
This is quite the challenge you have set yourself!