even the serve?I'm interested in eliminating the possibility of injury altogether that comes from flexion and whatnot.
Not backhand shots, these use supination. The serve has so small action it doesnt need pronation/supination. drives and overheads, yes. net shots... no.
Just do lots of drills. Use a whipping action with the elbow leading, bringing racket frame edge towards bird as if cutting into the bird. But at the last instant when the forearm whips forward, pronation brings racket face squarely onto the bird. Start slow, gradually faster when timing improves.